mb/google/brya/var/omnigul: Modify NVMe and UFS Storage support

[coreboot.git] / payloads / libpayload / drivers / video / graphics.c

/*
 *
 * Copyright (C) 2015 Google, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <libpayload.h>
#include <cbfs.h>
#include <fpmath.h>
#include <sysinfo.h>
#include "bitmap.h"

/*
 * 'canvas' is the drawing area located in the center of the screen. It's a
 * square area, stretching vertically to the edges of the screen, leaving
 * non-drawing areas on the left and right. The screen is assumed to be
 * landscape.
 */
static struct rect canvas;
static struct rect screen;

static uint8_t *gfx_buffer;

/*
 * Framebuffer is assumed to assign a higher coordinate (larger x, y) to
 * a higher address
 */
static const struct cb_framebuffer *fbinfo;

/* Shorthand for up-to-date virtual framebuffer address */
#define REAL_FB ((unsigned char *)phys_to_virt(fbinfo->physical_address))
#define FB      (gfx_buffer ? gfx_buffer : REAL_FB)

#define LOG(x...)       printf("CBGFX: " x)
#define PIVOT_H_MASK    (PIVOT_H_LEFT|PIVOT_H_CENTER|PIVOT_H_RIGHT)
#define PIVOT_V_MASK    (PIVOT_V_TOP|PIVOT_V_CENTER|PIVOT_V_BOTTOM)
#define ROUNDUP(x, y)   ((((x) + ((y) - 1)) / (y)) * (y))

static char initialized = 0;

static const struct vector vzero = {
        .x = 0,
        .y = 0,
};

struct color_transformation {
        uint8_t base;
        int16_t scale;
};

struct color_mapping {
        struct color_transformation red;
        struct color_transformation green;
        struct color_transformation blue;
        int enabled;
};

static struct color_mapping color_map;

static inline void set_color_trans(struct color_transformation *trans,
                                   uint8_t bg_color, uint8_t fg_color)
{
        trans->base = bg_color;
        trans->scale = fg_color - bg_color;
}

int set_color_map(const struct rgb_color *background,
                  const struct rgb_color *foreground)
{
        if (background == NULL || foreground == NULL)
                return CBGFX_ERROR_INVALID_PARAMETER;

        set_color_trans(&color_map.red, background->red, foreground->red);
        set_color_trans(&color_map.green, background->green,
                        foreground->green);
        set_color_trans(&color_map.blue, background->blue, foreground->blue);
        color_map.enabled = 1;

        return CBGFX_SUCCESS;
}

void clear_color_map(void)
{
        color_map.enabled = 0;
}

struct blend_value {
        uint8_t alpha;
        struct rgb_color rgb;
};

static struct blend_value blend;

int set_blend(const struct rgb_color *rgb, uint8_t alpha)
{
        if (rgb == NULL)
                return CBGFX_ERROR_INVALID_PARAMETER;

        blend.alpha = alpha;
        blend.rgb = *rgb;

        return CBGFX_SUCCESS;
}

void clear_blend(void)
{
        blend.alpha = 0;
        blend.rgb.red = 0;
        blend.rgb.green = 0;
        blend.rgb.blue = 0;
}

static void add_vectors(struct vector *out,
                        const struct vector *v1, const struct vector *v2)
{
        out->x = v1->x + v2->x;
        out->y = v1->y + v2->y;
}

static int fraction_equal(const struct fraction *f1, const struct fraction *f2)
{
        return (int64_t)f1->n * f2->d == (int64_t)f2->n * f1->d;
}

static int is_valid_fraction(const struct fraction *f)
{
        return f->d != 0;
}

static int is_valid_scale(const struct scale *s)
{
        return is_valid_fraction(&s->x) && is_valid_fraction(&s->y);
}

static void reduce_fraction(struct fraction *out, int64_t n, int64_t d)
{
        /* Simplest way to reduce the fraction until fitting in int32_t */
        int shift = log2(MAX(ABS(n), ABS(d)) >> 31) + 1;
        out->n = n >> shift;
        out->d = d >> shift;
}

/* out = f1 + f2 */
static void add_fractions(struct fraction *out,
                          const struct fraction *f1, const struct fraction *f2)
{
        reduce_fraction(out,
                        (int64_t)f1->n * f2->d + (int64_t)f2->n * f1->d,
                        (int64_t)f1->d * f2->d);
}

/* out = f1 - f2 */
static void subtract_fractions(struct fraction *out,
                               const struct fraction *f1,
                               const struct fraction *f2)
{
        reduce_fraction(out,
                        (int64_t)f1->n * f2->d - (int64_t)f2->n * f1->d,
                        (int64_t)f1->d * f2->d);
}

static void add_scales(struct scale *out,
                       const struct scale *s1, const struct scale *s2)
{
        add_fractions(&out->x, &s1->x, &s2->x);
        add_fractions(&out->y, &s1->y, &s2->y);
}

/*
 * Transform a vector:
 *      x' = x * a_x + offset_x
 *      y' = y * a_y + offset_y
 */
static int transform_vector(struct vector *out,
                            const struct vector *in,
                            const struct scale *a,
                            const struct vector *offset)
{
        if (!is_valid_scale(a))
                return CBGFX_ERROR_INVALID_PARAMETER;
        out->x = (int64_t)a->x.n * in->x / a->x.d + offset->x;
        out->y = (int64_t)a->y.n * in->y / a->y.d + offset->y;
        return CBGFX_SUCCESS;
}

/*
 * Returns 1 if v is exclusively within box, 0 if v is inclusively within box,
 * or -1 otherwise.
 */
static int within_box(const struct vector *v, const struct rect *bound)
{
        if (v->x > bound->offset.x &&
            v->y > bound->offset.y &&
            v->x < bound->offset.x + bound->size.width &&
            v->y < bound->offset.y + bound->size.height)
                return 1;
        else if (v->x >= bound->offset.x &&
                 v->y >= bound->offset.y &&
                 v->x <= bound->offset.x + bound->size.width &&
                 v->y <= bound->offset.y + bound->size.height)
                return 0;
        else
                return -1;
}

/* Helper function that applies color_map to the color. */
static inline uint8_t apply_map(uint8_t color,
                                const struct color_transformation *trans)
{
        if (!color_map.enabled)
                return color;
        return trans->base + trans->scale * color / UINT8_MAX;
}

/*
 * Helper function that applies color and opacity from blend struct
 * into the color.
 */
static inline uint8_t apply_blend(uint8_t color, uint8_t blend_color)
{
        if (blend.alpha == 0 || color == blend_color)
                return color;

        return (color * (256 - blend.alpha) +
                blend_color * blend.alpha) / 256;
}

static inline uint32_t calculate_color(const struct rgb_color *rgb,
                                       uint8_t invert)
{
        uint32_t color = 0;

        color |= (apply_blend(apply_map(rgb->red, &color_map.red),
                              blend.rgb.red)
                  >> (8 - fbinfo->red_mask_size))
                 << fbinfo->red_mask_pos;
        color |= (apply_blend(apply_map(rgb->green, &color_map.green),
                              blend.rgb.green)
                  >> (8 - fbinfo->green_mask_size))
                 << fbinfo->green_mask_pos;
        color |= (apply_blend(apply_map(rgb->blue, &color_map.blue),
                              blend.rgb.blue)
                  >> (8 - fbinfo->blue_mask_size))
                 << fbinfo->blue_mask_pos;
        if (invert)
                color ^= 0xffffffff;
        return color;
}

/*
 * Plot a pixel in a framebuffer. This is called from tight loops. Keep it slim
 * and do the validation at callers' site.
 */
static inline void set_pixel(struct vector *coord, uint32_t color)
{
        const int bpp = fbinfo->bits_per_pixel;
        const int bpl = fbinfo->bytes_per_line;
        struct vector rcoord;
        int i;

        switch (fbinfo->orientation) {
        case CB_FB_ORIENTATION_NORMAL:
        default:
                rcoord.x = coord->x;
                rcoord.y = coord->y;
                break;
        case CB_FB_ORIENTATION_BOTTOM_UP:
                rcoord.x = screen.size.width - 1 - coord->x;
                rcoord.y = screen.size.height - 1 - coord->y;
                break;
        case CB_FB_ORIENTATION_LEFT_UP:
                rcoord.x = coord->y;
                rcoord.y = screen.size.width - 1 - coord->x;
                break;
        case CB_FB_ORIENTATION_RIGHT_UP:
                rcoord.x = screen.size.height - 1 - coord->y;
                rcoord.y = coord->x;
                break;
        }

        uint8_t * const pixel = FB + rcoord.y * bpl + rcoord.x * bpp / 8;
        for (i = 0; i < bpp / 8; i++)
                pixel[i] = (color >> (i * 8));
}

/*
 * Initializes the library. Automatically called by APIs. It sets up
 * the canvas and the framebuffer.
 */
static int cbgfx_init(void)
{
        if (initialized)
                return 0;

        fbinfo = &lib_sysinfo.framebuffer;

        if (!fbinfo->physical_address)
                return CBGFX_ERROR_FRAMEBUFFER_ADDR;

        switch (fbinfo->orientation) {
        default: /* Normal or rotated 180 degrees. */
                screen.size.width = fbinfo->x_resolution;
                screen.size.height = fbinfo->y_resolution;
                break;
        case CB_FB_ORIENTATION_LEFT_UP: /* 90 degree rotation. */
        case CB_FB_ORIENTATION_RIGHT_UP:
                screen.size.width = fbinfo->y_resolution;
                screen.size.height = fbinfo->x_resolution;
                break;
        }
        screen.offset.x = 0;
        screen.offset.y = 0;

        /* Calculate canvas size & offset. Canvas is always square. */
        if (screen.size.height > screen.size.width) {
                canvas.size.height = screen.size.width;
                canvas.size.width = canvas.size.height;
                canvas.offset.x = 0;
                canvas.offset.y = (screen.size.height - canvas.size.height) / 2;
        } else {
                canvas.size.height = screen.size.height;
                canvas.size.width = canvas.size.height;
                canvas.offset.x = (screen.size.width - canvas.size.width) / 2;
                canvas.offset.y = 0;
        }

        initialized = 1;
        LOG("cbgfx initialized: screen:width=%d, height=%d, offset=%d canvas:width=%d, height=%d, offset=%d\n",
            screen.size.width, screen.size.height, screen.offset.x,
            canvas.size.width, canvas.size.height, canvas.offset.x);

        return 0;
}

int draw_box(const struct rect *box, const struct rgb_color *rgb)
{
        struct vector top_left;
        struct vector p, t;

        if (cbgfx_init())
                return CBGFX_ERROR_INIT;

        const uint32_t color = calculate_color(rgb, 0);
        const struct scale top_left_s = {
                .x = { .n = box->offset.x, .d = CANVAS_SCALE, },
                .y = { .n = box->offset.y, .d = CANVAS_SCALE, }
        };
        const struct scale bottom_right_s = {
                .x = { .n = box->offset.x + box->size.x, .d = CANVAS_SCALE, },
                .y = { .n = box->offset.y + box->size.y, .d = CANVAS_SCALE, }
        };

        transform_vector(&top_left, &canvas.size, &top_left_s, &canvas.offset);
        transform_vector(&t, &canvas.size, &bottom_right_s, &canvas.offset);
        if (within_box(&t, &canvas) < 0) {
                LOG("Box exceeds canvas boundary\n");
                return CBGFX_ERROR_BOUNDARY;
        }

        for (p.y = top_left.y; p.y < t.y; p.y++)
                for (p.x = top_left.x; p.x < t.x; p.x++)
                        set_pixel(&p, color);

        return CBGFX_SUCCESS;
}

int draw_rounded_box(const struct scale *pos_rel, const struct scale *dim_rel,
                     const struct rgb_color *rgb,
                     const struct fraction *thickness,
                     const struct fraction *radius)
{
        struct scale pos_end_rel;
        struct vector top_left;
        struct vector p, t;

        if (cbgfx_init())
                return CBGFX_ERROR_INIT;

        const uint32_t color = calculate_color(rgb, 0);

        if (!is_valid_scale(pos_rel) || !is_valid_scale(dim_rel))
                return CBGFX_ERROR_INVALID_PARAMETER;

        add_scales(&pos_end_rel, pos_rel, dim_rel);
        transform_vector(&top_left, &canvas.size, pos_rel, &canvas.offset);
        transform_vector(&t, &canvas.size, &pos_end_rel, &canvas.offset);
        if (within_box(&t, &canvas) < 0) {
                LOG("Box exceeds canvas boundary\n");
                return CBGFX_ERROR_BOUNDARY;
        }

        if (!is_valid_fraction(thickness) || !is_valid_fraction(radius))
                return CBGFX_ERROR_INVALID_PARAMETER;

        struct scale thickness_scale = {
                .x = { .n = thickness->n, .d = thickness->d },
                .y = { .n = thickness->n, .d = thickness->d },
        };
        struct scale radius_scale = {
                .x = { .n = radius->n, .d = radius->d },
                .y = { .n = radius->n, .d = radius->d },
        };
        struct vector d, r, s;
        transform_vector(&d, &canvas.size, &thickness_scale, &vzero);
        transform_vector(&r, &canvas.size, &radius_scale, &vzero);
        const uint8_t has_thickness = d.x > 0 && d.y > 0;
        if (thickness->n != 0 && !has_thickness)
                LOG("Thickness truncated to 0\n");
        const uint8_t has_radius = r.x > 0 && r.y > 0;
        if (radius->n != 0 && !has_radius)
                LOG("Radius truncated to 0\n");
        if (has_radius) {
                if (d.x > r.x || d.y > r.y) {
                        LOG("Thickness cannot be greater than radius\n");
                        return CBGFX_ERROR_INVALID_PARAMETER;
                }
                if (r.x * 2 > t.x - top_left.x || r.y * 2 > t.y - top_left.y) {
                        LOG("Radius cannot be greater than half of the box\n");
                        return CBGFX_ERROR_INVALID_PARAMETER;
                }
        }

        /* Step 1: Draw edges */
        int32_t x_begin, x_end;
        if (has_thickness) {
                /* top */
                for (p.y = top_left.y; p.y < top_left.y + d.y; p.y++)
                        for (p.x = top_left.x + r.x; p.x < t.x - r.x; p.x++)
                                set_pixel(&p, color);
                /* bottom */
                for (p.y = t.y - d.y; p.y < t.y; p.y++)
                        for (p.x = top_left.x + r.x; p.x < t.x - r.x; p.x++)
                                set_pixel(&p, color);
                for (p.y = top_left.y + r.y; p.y < t.y - r.y; p.y++) {
                        /* left */
                        for (p.x = top_left.x; p.x < top_left.x + d.x; p.x++)
                                set_pixel(&p, color);
                        /* right */
                        for (p.x = t.x - d.x; p.x < t.x; p.x++)
                                set_pixel(&p, color);
                }
        } else {
                /* Fill the regions except circular sectors */
                for (p.y = top_left.y; p.y < t.y; p.y++) {
                        if (p.y >= top_left.y + r.y && p.y < t.y - r.y) {
                                x_begin = top_left.x;
                                x_end = t.x;
                        } else {
                                x_begin = top_left.x + r.x;
                                x_end = t.x - r.x;
                        }
                        for (p.x = x_begin; p.x < x_end; p.x++)
                                set_pixel(&p, color);
                }
        }

        if (!has_radius)
                return CBGFX_SUCCESS;

        /*
         * Step 2: Draw rounded corners
         * When has_thickness, only the border is drawn. With fixed thickness,
         * the time complexity is linear to the size of the box.
         */
        if (has_thickness) {
                s.x = r.x - d.x;
                s.y = r.y - d.y;
        } else {
                s.x = 0;
                s.y = 0;
        }

        /* Use 64 bits to avoid overflow */
        int32_t x, y;
        uint64_t yy;
        const uint64_t rrx = (uint64_t)r.x * r.x, rry = (uint64_t)r.y * r.y;
        const uint64_t ssx = (uint64_t)s.x * s.x, ssy = (uint64_t)s.y * s.y;
        x_begin = 0;
        x_end = 0;
        for (y = r.y - 1; y >= 0; y--) {
                /*
                 * The inequality is valid in the beginning of each iteration:
                 * y^2 + x_end^2 < r^2
                 */
                yy = (uint64_t)y * y;
                /* Check yy/ssy + xx/ssx < 1 */
                while (yy * ssx + x_begin * x_begin * ssy < ssx * ssy)
                        x_begin++;
                /* The inequality must be valid now: y^2 + x_begin >= s^2 */
                x = x_begin;
                /* Check yy/rry + xx/rrx < 1 */
                while (x < x_end || yy * rrx + x * x * rry < rrx * rry) {
                        /*
                         * Example sequence of (y, x) when s = (4, 4) and
                         * r = (5, 5):
                         *   [(4, 0), (4, 1), (4, 2), (3, 3), (2, 4),
                         *    (1, 4), (0, 4)].
                         * If s.x==s.y r.x==r.y, then the sequence will be
                         * symmetric, and x and y will range from 0 to (r-1).
                         */
                        /* top left */
                        p.y = top_left.y + r.y - 1 - y;
                        p.x = top_left.x + r.x - 1 - x;
                        set_pixel(&p, color);
                        /* top right */
                        p.y = top_left.y + r.y - 1 - y;
                        p.x = t.x - r.x + x;
                        set_pixel(&p, color);
                        /* bottom left */
                        p.y = t.y - r.y + y;
                        p.x = top_left.x + r.x - 1 - x;
                        set_pixel(&p, color);
                        /* bottom right */
                        p.y = t.y - r.y + y;
                        p.x = t.x - r.x + x;
                        set_pixel(&p, color);
                        x++;
                }
                x_end = x;
                /* (x_begin <= x_end) must hold now */
        }

        return CBGFX_SUCCESS;
}

int draw_line(const struct scale *pos1, const struct scale *pos2,
              const struct fraction *thickness, const struct rgb_color *rgb)
{
        struct fraction len;
        struct vector top_left;
        struct vector size;
        struct vector p, t;

        if (cbgfx_init())
                return CBGFX_ERROR_INIT;

        const uint32_t color = calculate_color(rgb, 0);

        if (!is_valid_fraction(thickness))
                return CBGFX_ERROR_INVALID_PARAMETER;

        transform_vector(&top_left, &canvas.size, pos1, &canvas.offset);
        if (fraction_equal(&pos1->y, &pos2->y)) {
                /* Horizontal line */
                subtract_fractions(&len, &pos2->x, &pos1->x);
                struct scale dim = {
                        .x = { .n = len.n, .d = len.d },
                        .y = { .n = thickness->n, .d = thickness->d },
                };
                transform_vector(&size, &canvas.size, &dim, &vzero);
                size.y = MAX(size.y, 1);
        } else if (fraction_equal(&pos1->x, &pos2->x)) {
                /* Vertical line */
                subtract_fractions(&len, &pos2->y, &pos1->y);
                struct scale dim = {
                        .x = { .n = thickness->n, .d = thickness->d },
                        .y = { .n = len.n, .d = len.d },
                };
                transform_vector(&size, &canvas.size, &dim, &vzero);
                size.x = MAX(size.x, 1);
        } else {
                LOG("Only support horizontal and vertical lines\n");
                return CBGFX_ERROR_INVALID_PARAMETER;
        }

        add_vectors(&t, &top_left, &size);
        if (within_box(&t, &canvas) < 0) {
                LOG("Line exceeds canvas boundary\n");
                return CBGFX_ERROR_BOUNDARY;
        }

        for (p.y = top_left.y; p.y < t.y; p.y++)
                for (p.x = top_left.x; p.x < t.x; p.x++)
                        set_pixel(&p, color);

        return CBGFX_SUCCESS;
}

int clear_canvas(const struct rgb_color *rgb)
{
        const struct rect box = {
                vzero,
                .size = {
                        .width = CANVAS_SCALE,
                        .height = CANVAS_SCALE,
                },
        };

        if (cbgfx_init())
                return CBGFX_ERROR_INIT;

        return draw_box(&box, rgb);
}

int clear_screen(const struct rgb_color *rgb)
{
        if (cbgfx_init())
                return CBGFX_ERROR_INIT;

        int x, y, i;
        uint32_t color = calculate_color(rgb, 0);
        const int bpp = fbinfo->bits_per_pixel;
        const int bpl = fbinfo->bytes_per_line;
        uint8_t *line = malloc(bpl);

        if (!line) {
                LOG("Failed to allocate line buffer (%u bytes)\n", bpl);
                return CBGFX_ERROR_UNKNOWN;
        }

        /* Set line buffer pixels, then memcpy to framebuffer */
        for (x = 0; x < fbinfo->x_resolution; x++)
                for (i = 0; i < bpp / 8; i++)
                        line[x * bpp / 8 + i] = (color >> (i * 8));
        for (y = 0; y < fbinfo->y_resolution; y++)
                memcpy(FB + y * bpl, line, bpl);

        free(line);
        return CBGFX_SUCCESS;
}

static int pal_to_rgb(uint8_t index, const struct bitmap_palette_element_v3 *pal,
                      size_t palcount, struct rgb_color *out)
{
        if (index >= palcount) {
                LOG("Color index %d exceeds palette boundary\n", index);
                return CBGFX_ERROR_BITMAP_DATA;
        }

        out->red = pal[index].red;
        out->green = pal[index].green;
        out->blue = pal[index].blue;
        return CBGFX_SUCCESS;
}

/*
 * We're using the Lanczos resampling algorithm to rescale images to a new size.
 * Since output size is often not cleanly divisible by input size, an output
 * pixel (ox,oy) corresponds to a point that lies in the middle between several
 * input pixels (ix,iy), meaning that if you transformed the coordinates of the
 * output pixel into the input image space, they would be fractional. To sample
 * the color of this "virtual" pixel with fractional coordinates, we gather the
 * 6x6 grid of nearest real input pixels in a sample array. Then we multiply the
 * color values for each of those pixels (separately for red, green and blue)
 * with a "weight" value that was calculated from the distance between that
 * input pixel and the fractional output pixel coordinates. This is done for
 * both X and Y dimensions separately. The combined weights for all 36 sample
 * pixels add up to 1.0, so by adding up the multiplied color values we get the
 * interpolated color for the output pixel.
 *
 * The CONFIG_LP_CBGFX_FAST_RESAMPLE option let's the user change the 'a'
 * parameter from the Lanczos weight formula from 3 to 2, which effectively
 * reduces the size of the sample array from 6x6 to 4x4. This is a bit faster
 * but doesn't look as good. Most use cases should be fine without it.
 */
#if CONFIG(LP_CBGFX_FAST_RESAMPLE)
#define LNCZ_A 2
#else
#define LNCZ_A 3
#endif

/*
 * When walking the sample array we often need to start at a pixel close to our
 * fractional output pixel (for convenience we choose the pixel on the top-left
 * which corresponds to the integer parts of the output pixel coordinates) and
 * then work our way outwards in both directions from there. Arrays in C must
 * start at 0 but we'd really prefer indexes to go from -2 to 3 (for 6x6)
 * instead, so that this "start pixel" could be 0. Since we cannot do that,
 * define a constant for the index of that "0th" pixel instead.
 */
#define S0 (LNCZ_A - 1)

/* The size of the sample array, which we need a lot. */
#define SSZ (LNCZ_A * 2)

/*
 * This is implementing the Lanczos kernel according to:
 * https://en.wikipedia.org/wiki/Lanczos_resampling
 *
 *         / 1                                                  if x = 0
 * L(x) = <  a * sin(pi * x) * sin(pi * x / a) / (pi^2 * x^2)   if -a < x <= a
 *         \ 0                                                  otherwise
 */
static fpmath_t lanczos_weight(fpmath_t in, int off)
{
        /*
         * |in| is the output pixel coordinate scaled into the input pixel
         * space. |off| is the offset in the sample array for the pixel whose
         * weight we're calculating. (off - S0) is the distance from that
         * sample pixel to the S0 pixel, and the fractional part of |in|
         * (in - floor(in)) is by definition the distance between S0 and the
         * output pixel.
         *
         * So (off - S0) - (in - floor(in)) is the distance from the sample
         * pixel to S0 minus the distance from S0 to the output pixel, aka
         * the distance from the sample pixel to the output pixel.
         */
        fpmath_t x = fpisub(off - S0, fpsubi(in, fpfloor(in)));

        if (fpequals(x, fp(0)))
                return fp(1);

        /* x * 2 / a can save some instructions if a == 2 */
        fpmath_t x2a = x;
        if (LNCZ_A != 2)
                x2a = fpmul(x, fpfrac(2, LNCZ_A));

        fpmath_t x_times_pi = fpmul(x, fppi());

        /*
         * Rather than using sinr(pi*x), we leverage the "one-based" sine
         * function (see <fpmath.h>) with sin1(2*x) so that the pi is eliminated
         * since multiplication by an integer is a slightly faster operation.
         */
        fpmath_t tmp = fpmuli(fpdiv(fpsin1(fpmuli(x, 2)), x_times_pi), LNCZ_A);
        return fpdiv(fpmul(tmp, fpsin1(x2a)), x_times_pi);
}

static int draw_bitmap_v3(const struct vector *top_left,
                          const struct vector *dim,
                          const struct vector *dim_org,
                          const struct bitmap_header_v3 *header,
                          const struct bitmap_palette_element_v3 *pal,
                          const uint8_t *pixel_array, uint8_t invert)
{
        const int bpp = header->bits_per_pixel;
        int32_t dir;
        struct vector p;
        int32_t ox, oy;         /* output (resampled) pixel coordinates */
        int32_t ix, iy;         /* input (source image) pixel coordinates */
        int sx, sy;     /* index into |sample| (not ringbuffer adjusted) */

        if (header->compression) {
                LOG("Compressed bitmaps are not supported\n");
                return CBGFX_ERROR_BITMAP_FORMAT;
        }
        if (bpp >= 16) {
                LOG("Non-palette bitmaps are not supported\n");
                return CBGFX_ERROR_BITMAP_FORMAT;
        }
        if (bpp != 8) {
                LOG("Unsupported bits per pixel: %d\n", bpp);
                return CBGFX_ERROR_BITMAP_FORMAT;
        }

        const int32_t y_stride = ROUNDUP(dim_org->width * bpp / 8, 4);
        /*
         * header->height can be positive or negative.
         *
         * If it's negative, pixel data is stored from top to bottom. We render
         * image from the lowest row to the highest row.
         *
         * If it's positive, pixel data is stored from bottom to top. We render
         * image from the highest row to the lowest row.
         */
        p.y = top_left->y;
        if (header->height < 0) {
                dir = 1;
        } else {
                p.y += dim->height - 1;
                dir = -1;
        }

        /* Don't waste time resampling when the scale is 1:1. */
        if (dim_org->width == dim->width && dim_org->height == dim->height) {
                for (oy = 0; oy < dim->height; oy++, p.y += dir) {
                        p.x = top_left->x;
                        for (ox = 0; ox < dim->width; ox++, p.x++) {
                                struct rgb_color rgb;
                                if (pal_to_rgb(pixel_array[oy * y_stride + ox],
                                               pal, header->colors_used, &rgb))
                                        return CBGFX_ERROR_BITMAP_DATA;
                                set_pixel(&p, calculate_color(&rgb, invert));
                        }
                }
                return CBGFX_SUCCESS;
        }

        /* Precalculate the X-weights for every possible ox so that we only have
           to multiply weights together in the end. */
        fpmath_t (*weight_x)[SSZ] = malloc(sizeof(fpmath_t) * SSZ * dim->width);
        if (!weight_x)
                return CBGFX_ERROR_UNKNOWN;
        for (ox = 0; ox < dim->width; ox++) {
                for (sx = 0; sx < SSZ; sx++) {
                        fpmath_t ixfp = fpfrac(ox * dim_org->width, dim->width);
                        weight_x[ox][sx] = lanczos_weight(ixfp, sx);
                }
        }

        /*
         * For every sy in the sample array, we directly cache a pointer into
         * the .BMP pixel array for the start of the corresponding line. On the
         * edges of the image (where we don't have any real pixels to fill all
         * lines in the sample array), we just reuse the last valid lines inside
         * the image for all lines that would lie outside.
         */
        const uint8_t *ypix[SSZ];
        for (sy = 0; sy < SSZ; sy++) {
                if (sy <= S0)
                        ypix[sy] = pixel_array;
                else if (sy - S0 >= dim_org->height)
                        ypix[sy] = ypix[sy - 1];
                else
                        ypix[sy] = &pixel_array[y_stride * (sy - S0)];
        }

        /* iy and ix track the input pixel corresponding to sample[S0][S0]. */
        iy = 0;
        for (oy = 0; oy < dim->height; oy++, p.y += dir) {
                struct rgb_color sample[SSZ][SSZ];

                /* Like with X weights, we also cache all Y weights. */
                fpmath_t iyfp = fpfrac(oy * dim_org->height, dim->height);
                fpmath_t weight_y[SSZ];
                for (sy = 0; sy < SSZ; sy++)
                        weight_y[sy] = lanczos_weight(iyfp, sy);

                /*
                 * If we have a new input pixel line between the last oy and
                 * this one, we have to adjust iy forward. When upscaling, this
                 * is not always the case for each new output line. When
                 * downscaling, we may even cross more than one line per output
                 * pixel.
                 */
                while (fpfloor(iyfp) > iy) {
                        iy++;

                        /* Shift ypix array up to center around next iy line. */
                        for (sy = 0; sy < SSZ - 1; sy++)
                                ypix[sy] = ypix[sy + 1];

                        /* Calculate the last ypix that is being shifted in,
                           but beware of reaching the end of the input image. */
                        if (iy + LNCZ_A < dim_org->height)
                                ypix[SSZ - 1] = &pixel_array[y_stride *
                                                             (iy + LNCZ_A)];
                }

                /*
                 * Initialize the sample array for this line, and also
                 * the equals counter, which counts how many of the latest
                 * pixels were exactly equal.
                 */
                int equals = 0;
                uint8_t last_equal = ypix[0][0];
                for (sx = 0; sx < SSZ; sx++) {
                        for (sy = 0; sy < SSZ; sy++) {
                                if (sx - S0 >= dim_org->width) {
                                        sample[sx][sy] = sample[sx - 1][sy];
                                        equals++;
                                        continue;
                                }
                                /*
                                 * For pixels to the left of S0 there are no
                                 * corresponding input pixels so just use
                                 * ypix[sy][0].
                                 */
                                uint8_t i = ypix[sy][MAX(0, sx - S0)];
                                if (pal_to_rgb(i, pal, header->colors_used,
                                               &sample[sx][sy]))
                                        goto bitmap_error;
                                if (i == last_equal) {
                                        equals++;
                                } else {
                                        last_equal = i;
                                        equals = 1;
                                }
                        }
                }

                ix = 0;
                p.x = top_left->x;
                for (ox = 0; ox < dim->width; ox++, p.x++) {
                        /* Adjust ix forward, same as iy above. */
                        fpmath_t ixfp = fpfrac(ox * dim_org->width, dim->width);
                        while (fpfloor(ixfp) > ix) {
                                ix++;

                                /*
                                 * We want to reuse the sample columns we
                                 * already have, but we don't want to copy them
                                 * all around for every new column either.
                                 * Instead, treat the X dimension of the sample
                                 * array like a ring buffer indexed by ix. rx is
                                 * the ringbuffer-adjusted offset of the new
                                 * column in sample (the rightmost one) we're
                                 * trying to fill.
                                 */
                                int rx = (SSZ - 1 + ix) % SSZ;
                                for (sy = 0; sy < SSZ; sy++) {
                                        if (ix + LNCZ_A >= dim_org->width) {
                                                sample[rx][sy] = sample[(SSZ - 2
                                                        + ix) % SSZ][sy];
                                                equals++;
                                                continue;
                                        }
                                        uint8_t i = ypix[sy][ix + LNCZ_A];
                                        if (i == last_equal) {
                                                if (equals++ >= (SSZ * SSZ))
                                                        continue;
                                        } else {
                                                last_equal = i;
                                                equals = 1;
                                        }
                                        if (pal_to_rgb(i, pal,
                                                       header->colors_used,
                                                       &sample[rx][sy]))
                                                goto bitmap_error;
                                }
                        }

                        /* If all pixels in sample are equal, fast path. */
                        if (equals >= (SSZ * SSZ)) {
                                set_pixel(&p, calculate_color(&sample[0][0],
                                                              invert));
                                continue;
                        }

                        fpmath_t red = fp(0);
                        fpmath_t green = fp(0);
                        fpmath_t blue = fp(0);
                        for (sy = 0; sy < SSZ; sy++) {
                                for (sx = 0; sx < SSZ; sx++) {
                                        int rx = (sx + ix) % SSZ;
                                        fpmath_t weight = fpmul(weight_x[ox][sx],
                                                                weight_y[sy]);
                                        red = fpadd(red, fpmuli(weight,
                                                sample[rx][sy].red));
                                        green = fpadd(green, fpmuli(weight,
                                                sample[rx][sy].green));
                                        blue = fpadd(blue, fpmuli(weight,
                                                sample[rx][sy].blue));
                                }
                        }

                        /*
                         * Weights *should* sum up to 1.0 (making this not
                         * necessary) but just to hedge against rounding errors
                         * we should clamp color values to their legal limits.
                         */
                        struct rgb_color rgb = {
                                .red = MAX(0, MIN(UINT8_MAX, fpround(red))),
                                .green = MAX(0, MIN(UINT8_MAX, fpround(green))),
                                .blue = MAX(0, MIN(UINT8_MAX, fpround(blue))),
                        };

                        set_pixel(&p, calculate_color(&rgb, invert));
                }
        }

        free(weight_x);
        return CBGFX_SUCCESS;

bitmap_error:
        free(weight_x);
        return CBGFX_ERROR_BITMAP_DATA;
}

static int get_bitmap_file_header(const void *bitmap, size_t size,
                                  struct bitmap_file_header *file_header)
{
        const struct bitmap_file_header *fh;

        if (sizeof(*file_header) > size) {
                LOG("Invalid bitmap data\n");
                return CBGFX_ERROR_BITMAP_DATA;
        }
        fh = (struct bitmap_file_header *)bitmap;
        if (fh->signature[0] != 'B' || fh->signature[1] != 'M') {
                LOG("Bitmap signature mismatch\n");
                return CBGFX_ERROR_BITMAP_SIGNATURE;
        }
        file_header->file_size = le32toh(fh->file_size);
        if (file_header->file_size != size) {
                LOG("Bitmap file size does not match cbfs file size\n");
                return CBGFX_ERROR_BITMAP_DATA;
        }
        file_header->bitmap_offset = le32toh(fh->bitmap_offset);

        return CBGFX_SUCCESS;
}

static int parse_bitmap_header_v3(
                        const uint8_t *bitmap,
                        size_t size,
                        /* ^--- IN / OUT ---v */
                        struct bitmap_header_v3 *header,
                        const struct bitmap_palette_element_v3 **palette,
                        const uint8_t **pixel_array,
                        struct vector *dim_org)
{
        struct bitmap_file_header file_header;
        struct bitmap_header_v3 *h;
        int rv;

        rv = get_bitmap_file_header(bitmap, size, &file_header);
        if (rv)
                return rv;

        size_t header_offset = sizeof(struct bitmap_file_header);
        size_t header_size = sizeof(struct bitmap_header_v3);
        size_t palette_offset = header_offset + header_size;
        size_t file_size = file_header.file_size;

        h = (struct bitmap_header_v3 *)(bitmap + header_offset);
        header->header_size = le32toh(h->header_size);
        if (header->header_size != header_size) {
                LOG("Unsupported bitmap format\n");
                return CBGFX_ERROR_BITMAP_FORMAT;
        }

        header->width = le32toh(h->width);
        header->height = le32toh(h->height);
        if (header->width == 0 || header->height == 0) {
                LOG("Invalid image width or height\n");
                return CBGFX_ERROR_BITMAP_DATA;
        }
        dim_org->width = header->width;
        dim_org->height = ABS(header->height);

        header->bits_per_pixel = le16toh(h->bits_per_pixel);
        header->compression = le32toh(h->compression);
        header->size = le32toh(h->size);
        header->colors_used = le32toh(h->colors_used);
        size_t palette_size = header->colors_used
                        * sizeof(struct bitmap_palette_element_v3);
        size_t pixel_offset = file_header.bitmap_offset;
        if (pixel_offset > file_size) {
                LOG("Bitmap pixel data exceeds buffer boundary\n");
                return CBGFX_ERROR_BITMAP_DATA;
        }
        if (palette_offset + palette_size > pixel_offset) {
                LOG("Bitmap palette data exceeds palette boundary\n");
                return CBGFX_ERROR_BITMAP_DATA;
        }
        *palette = (struct bitmap_palette_element_v3 *)(bitmap +
                        palette_offset);

        size_t pixel_size = header->size;
        if (pixel_size != dim_org->height *
                ROUNDUP(dim_org->width * header->bits_per_pixel / 8, 4)) {
                LOG("Bitmap pixel array size does not match expected size\n");
                return CBGFX_ERROR_BITMAP_DATA;
        }
        if (pixel_offset + pixel_size > file_size) {
                LOG("Bitmap pixel array exceeds buffer boundary\n");
                return CBGFX_ERROR_BITMAP_DATA;
        }
        *pixel_array = bitmap + pixel_offset;

        return CBGFX_SUCCESS;
}

/*
 * This calculates the dimension of the image projected on the canvas from the
 * dimension relative to the canvas size. If either width or height is zero, it
 * is derived from the other (non-zero) value to keep the aspect ratio.
 */
static int calculate_dimension(const struct vector *dim_org,
                               const struct scale *dim_rel,
                               struct vector *dim)
{
        if (dim_rel->x.n == 0 && dim_rel->y.n == 0)
                return CBGFX_ERROR_INVALID_PARAMETER;

        if (dim_rel->x.n > dim_rel->x.d || dim_rel->y.n > dim_rel->y.d)
                return CBGFX_ERROR_INVALID_PARAMETER;

        if (dim_rel->x.n > 0) {
                if (!is_valid_fraction(&dim_rel->x))
                        return CBGFX_ERROR_INVALID_PARAMETER;
                dim->width = canvas.size.width  * dim_rel->x.n / dim_rel->x.d;
        }
        if (dim_rel->y.n > 0) {
                if (!is_valid_fraction(&dim_rel->y))
                        return CBGFX_ERROR_INVALID_PARAMETER;
                dim->height = canvas.size.height * dim_rel->y.n / dim_rel->y.d;
        }

        /* Derive height from width using aspect ratio */
        if (dim_rel->y.n == 0)
                dim->height = dim->width * dim_org->height / dim_org->width;
        /* Derive width from height using aspect ratio */
        if (dim_rel->x.n == 0)
                dim->width = dim->height * dim_org->width / dim_org->height;

        return CBGFX_SUCCESS;
}

static int calculate_position(const struct vector *dim,
                              const struct scale *pos_rel, uint8_t pivot,
                              struct vector *top_left)
{
        int rv;

        rv = transform_vector(top_left, &canvas.size, pos_rel, &canvas.offset);
        if (rv)
                return rv;

        switch (pivot & PIVOT_H_MASK) {
        case PIVOT_H_LEFT:
                break;
        case PIVOT_H_CENTER:
                top_left->x -= dim->width / 2;
                break;
        case PIVOT_H_RIGHT:
                top_left->x -= dim->width;
                break;
        default:
                return CBGFX_ERROR_INVALID_PARAMETER;
        }

        switch (pivot & PIVOT_V_MASK) {
        case PIVOT_V_TOP:
                break;
        case PIVOT_V_CENTER:
                top_left->y -= dim->height / 2;
                break;
        case PIVOT_V_BOTTOM:
                top_left->y -= dim->height;
                break;
        default:
                return CBGFX_ERROR_INVALID_PARAMETER;
        }

        return CBGFX_SUCCESS;
}

static int check_boundary(const struct vector *top_left,
                          const struct vector *dim,
                          const struct rect *bound)
{
        struct vector v;
        add_vectors(&v, dim, top_left);
        if (top_left->x < bound->offset.x
                        || top_left->y < bound->offset.y
                        || within_box(&v, bound) < 0)
                return CBGFX_ERROR_BOUNDARY;
        return CBGFX_SUCCESS;
}

int draw_bitmap(const void *bitmap, size_t size,
                const struct scale *pos_rel, const struct scale *dim_rel,
                uint32_t flags)
{
        struct bitmap_header_v3 header;
        const struct bitmap_palette_element_v3 *palette;
        const uint8_t *pixel_array;
        struct vector top_left, dim, dim_org;
        int rv;
        const uint8_t pivot = flags & PIVOT_MASK;
        const uint8_t invert = (flags & INVERT_COLORS) >> INVERT_SHIFT;

        if (cbgfx_init())
                return CBGFX_ERROR_INIT;

        /* only v3 is supported now */
        rv = parse_bitmap_header_v3(bitmap, size,
                                    &header, &palette, &pixel_array, &dim_org);
        if (rv)
                return rv;

        /* Calculate height and width of the image */
        rv = calculate_dimension(&dim_org, dim_rel, &dim);
        if (rv)
                return rv;

        /* Calculate coordinate */
        rv = calculate_position(&dim, pos_rel, pivot, &top_left);
        if (rv)
                return rv;

        rv = check_boundary(&top_left, &dim, &canvas);
        if (rv) {
                LOG("Bitmap image exceeds canvas boundary\n");
                return rv;
        }

        return draw_bitmap_v3(&top_left, &dim, &dim_org,
                              &header, palette, pixel_array, invert);
}

int draw_bitmap_direct(const void *bitmap, size_t size,
                       const struct vector *top_left)
{
        struct bitmap_header_v3 header;
        const struct bitmap_palette_element_v3 *palette;
        const uint8_t *pixel_array;
        struct vector dim;
        int rv;

        if (cbgfx_init())
                return CBGFX_ERROR_INIT;

        /* only v3 is supported now */
        rv = parse_bitmap_header_v3(bitmap, size,
                                    &header, &palette, &pixel_array, &dim);
        if (rv)
                return rv;

        rv = check_boundary(top_left, &dim, &screen);
        if (rv) {
                LOG("Bitmap image exceeds screen boundary\n");
                return rv;
        }

        return draw_bitmap_v3(top_left, &dim, &dim,
                              &header, palette, pixel_array, 0);
}

int get_bitmap_dimension(const void *bitmap, size_t sz, struct scale *dim_rel)
{
        struct bitmap_header_v3 header;
        const struct bitmap_palette_element_v3 *palette;
        const uint8_t *pixel_array;
        struct vector dim, dim_org;
        int rv;

        if (cbgfx_init())
                return CBGFX_ERROR_INIT;

        /* Only v3 is supported now */
        rv = parse_bitmap_header_v3(bitmap, sz,
                                    &header, &palette, &pixel_array, &dim_org);
        if (rv)
                return rv;

        /* Calculate height and width of the image */
        rv = calculate_dimension(&dim_org, dim_rel, &dim);
        if (rv)
                return rv;

        /* Calculate size relative to the canvas */
        dim_rel->x.n = dim.width;
        dim_rel->x.d = canvas.size.width;
        dim_rel->y.n = dim.height;
        dim_rel->y.d = canvas.size.height;

        return CBGFX_SUCCESS;
}

int enable_graphics_buffer(void)
{
        if (gfx_buffer)
                return CBGFX_SUCCESS;

        if (cbgfx_init())
                return CBGFX_ERROR_INIT;

        size_t buffer_size = fbinfo->y_resolution * fbinfo->bytes_per_line;
        gfx_buffer = malloc(buffer_size);
        if (!gfx_buffer) {
                LOG("%s: Failed to create graphics buffer (%zu bytes).\n",
                    __func__, buffer_size);
                return CBGFX_ERROR_GRAPHICS_BUFFER;
        }

        return CBGFX_SUCCESS;
}

int flush_graphics_buffer(void)
{
        if (!gfx_buffer)
                return CBGFX_ERROR_GRAPHICS_BUFFER;

        memcpy(REAL_FB, gfx_buffer, fbinfo->y_resolution * fbinfo->bytes_per_line);
        return CBGFX_SUCCESS;
}

void disable_graphics_buffer(void)
{
        free(gfx_buffer);
        gfx_buffer = NULL;
}