skia/ext/bitmap_platform_device_cairo.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "skia/ext/bitmap_platform_device_cairo.h"
   6 #include "skia/ext/platform_canvas.h"
   7
   8 #if defined(OS_OPENBSD)
   9 #include <cairo.h>
  10 #else
  11 #include <cairo/cairo.h>
  12 #endif
  13
  14 namespace skia {
  15
  16 namespace {
  17
  18 void CairoSurfaceReleaseProc(void*, void* context) {
  19   SkASSERT(context);
  20   cairo_surface_destroy(static_cast<cairo_surface_t*>(context));
  21 }
  22
  23 // Back the destination bitmap by a Cairo surface.  The bitmap's
  24 // pixelRef takes ownership of the passed-in surface and will call
  25 // cairo_surface_destroy() upon destruction.
  26 //
  27 // Note: it may immediately destroy the surface, if it fails to create a bitmap
  28 // with pixels, thus the caller must either ref() the surface before hand, or
  29 // it must not refer to the surface after this call.
  30 bool InstallCairoSurfacePixels(SkBitmap* dst,
  31                                cairo_surface_t* surface,
  32                                bool is_opaque) {
  33   SkASSERT(dst);
  34   if (!surface) {
  35     return false;
  36   }
  37   SkImageInfo info
  38       = SkImageInfo::MakeN32Premul(cairo_image_surface_get_width(surface),
  39                                    cairo_image_surface_get_height(surface));
  40   return dst->installPixels(info,
  41                             cairo_image_surface_get_data(surface),
  42                             cairo_image_surface_get_stride(surface),
  43                             &CairoSurfaceReleaseProc,
  44                             static_cast<void*>(surface));
  45 }
  46
  47 void LoadMatrixToContext(cairo_t* context, const SkMatrix& matrix) {
  48   cairo_matrix_t cairo_matrix;
  49   cairo_matrix_init(&cairo_matrix,
  50                     SkScalarToFloat(matrix.getScaleX()),
  51                     SkScalarToFloat(matrix.getSkewY()),
  52                     SkScalarToFloat(matrix.getSkewX()),
  53                     SkScalarToFloat(matrix.getScaleY()),
  54                     SkScalarToFloat(matrix.getTranslateX()),
  55                     SkScalarToFloat(matrix.getTranslateY()));
  56   cairo_set_matrix(context, &cairo_matrix);
  57 }
  58
  59 void LoadClipToContext(cairo_t* context, const SkRegion& clip) {
  60   cairo_reset_clip(context);
  61
  62   // TODO(brettw) support non-rect clips.
  63   SkIRect bounding = clip.getBounds();
  64   cairo_rectangle(context, bounding.fLeft, bounding.fTop,
  65                   bounding.fRight - bounding.fLeft,
  66                   bounding.fBottom - bounding.fTop);
  67   cairo_clip(context);
  68 }
  69
  70 }  // namespace
  71
  72 void BitmapPlatformDevice::SetMatrixClip(
  73     const SkMatrix& transform,
  74     const SkRegion& region) {
  75   transform_ = transform;
  76   clip_region_ = region;
  77   config_dirty_ = true;
  78 }
  79
  80 void BitmapPlatformDevice::LoadConfig() {
  81   if (!config_dirty_ || !cairo_)
  82     return;  // Nothing to do.
  83   config_dirty_ = false;
  84
  85   // Load the identity matrix since this is what our clip is relative to.
  86   cairo_matrix_t cairo_matrix;
  87   cairo_matrix_init_identity(&cairo_matrix);
  88   cairo_set_matrix(cairo_, &cairo_matrix);
  89
  90   LoadClipToContext(cairo_, clip_region_);
  91   LoadMatrixToContext(cairo_, transform_);
  92 }
  93
  94 // We use this static factory function instead of the regular constructor so
  95 // that we can create the pixel data before calling the constructor. This is
  96 // required so that we can call the base class' constructor with the pixel
  97 // data.
  98 BitmapPlatformDevice* BitmapPlatformDevice::Create(int width, int height,
  99                                                    bool is_opaque,
 100                                                    cairo_surface_t* surface) {
 101   if (cairo_surface_status(surface) != CAIRO_STATUS_SUCCESS) {
 102     cairo_surface_destroy(surface);
 103     return NULL;
 104   }
 105
 106   // must call this before trying to install the surface, since that may result
 107   // in the surface being destroyed.
 108   cairo_t* cairo = cairo_create(surface);
 109
 110   SkBitmap bitmap;
 111   if (!InstallCairoSurfacePixels(&bitmap, surface, is_opaque)) {
 112     cairo_destroy(cairo);
 113     return NULL;
 114   }
 115
 116   // The device object will take ownership of the graphics context.
 117   return new BitmapPlatformDevice(bitmap, cairo);
 118 }
 119
 120 BitmapPlatformDevice* BitmapPlatformDevice::Create(int width, int height,
 121                                                    bool is_opaque) {
 122   // This initializes the bitmap to all zeros.
 123   cairo_surface_t* surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32,
 124                                                         width, height);
 125
 126   BitmapPlatformDevice* device = Create(width, height, is_opaque, surface);
 127
 128 #ifndef NDEBUG
 129   if (device && is_opaque)  // Fill with bright bluish green
 130     device->eraseColor(SkColorSetARGB(255, 0, 255, 128));
 131 #endif
 132
 133   return device;
 134 }
 135
 136 BitmapPlatformDevice* BitmapPlatformDevice::CreateAndClear(int width,
 137                                                            int height,
 138                                                            bool is_opaque) {
 139   // The Linux port always constructs initialized bitmaps, so there is no extra
 140   // work to perform here.
 141   return Create(width, height, is_opaque);
 142 }
 143
 144 BitmapPlatformDevice* BitmapPlatformDevice::Create(int width, int height,
 145                                                    bool is_opaque,
 146                                                    uint8_t* data) {
 147   cairo_surface_t* surface = cairo_image_surface_create_for_data(
 148       data, CAIRO_FORMAT_ARGB32, width, height,
 149       cairo_format_stride_for_width(CAIRO_FORMAT_ARGB32, width));
 150
 151   return Create(width, height, is_opaque, surface);
 152 }
 153
 154 // Ownership of the cairo object is transferred.
 155 BitmapPlatformDevice::BitmapPlatformDevice(
 156     const SkBitmap& bitmap,
 157     cairo_t* cairo)
 158     : SkBitmapDevice(bitmap),
 159       cairo_(cairo),
 160       config_dirty_(true),
 161       transform_(SkMatrix::I()) {  // Want to load the config next time.
 162   SetPlatformDevice(this, this);
 163 }
 164
 165 BitmapPlatformDevice::~BitmapPlatformDevice() {
 166   cairo_destroy(cairo_);
 167 }
 168
 169 SkBaseDevice* BitmapPlatformDevice::onCreateDevice(const SkImageInfo& info,
 170                                                    Usage /*usage*/) {
 171   SkASSERT(info.colorType() == kPMColor_SkColorType);
 172   return BitmapPlatformDevice::Create(info.width(), info.height(),
 173                                       info.isOpaque());
 174 }
 175
 176 cairo_t* BitmapPlatformDevice::BeginPlatformPaint() {
 177   LoadConfig();
 178   cairo_surface_t* surface = cairo_get_target(cairo_);
 179   // Tell cairo to flush anything it has pending.
 180   cairo_surface_flush(surface);
 181   // Tell Cairo that we (probably) modified (actually, will modify) its pixel
 182   // buffer directly.
 183   cairo_surface_mark_dirty(surface);
 184   return cairo_;
 185 }
 186
 187 void BitmapPlatformDevice::DrawToNativeContext(
 188     PlatformSurface surface, int x, int y, const PlatformRect* src_rect) {
 189   // Should never be called on Linux.
 190   SkASSERT(false);
 191 }
 192
 193 void BitmapPlatformDevice::setMatrixClip(const SkMatrix& transform,
 194                                          const SkRegion& region,
 195                                          const SkClipStack&) {
 196   SetMatrixClip(transform, region);
 197 }
 198
 199 // PlatformCanvas impl
 200
 201 SkCanvas* CreatePlatformCanvas(int width, int height, bool is_opaque,
 202                                uint8_t* data, OnFailureType failureType) {
 203   skia::RefPtr<SkBaseDevice> dev = skia::AdoptRef(
 204       BitmapPlatformDevice::Create(width, height, is_opaque, data));
 205   return CreateCanvas(dev, failureType);
 206 }
 207
 208 // Port of PlatformBitmap to linux
 209 PlatformBitmap::~PlatformBitmap() {
 210   cairo_destroy(surface_);
 211 }
 212
 213 bool PlatformBitmap::Allocate(int width, int height, bool is_opaque) {
 214   // The SkBitmap allocates and owns the bitmap memory; PlatformBitmap owns the
 215   // cairo drawing context tied to the bitmap. The SkBitmap's pixelRef can
 216   // outlive the PlatformBitmap if additional copies are made.
 217   int stride = cairo_format_stride_for_width(CAIRO_FORMAT_ARGB32, width);
 218
 219   cairo_surface_t* surf = cairo_image_surface_create(
 220       CAIRO_FORMAT_ARGB32,
 221       width,
 222       height);
 223   if (cairo_surface_status(surf) != CAIRO_STATUS_SUCCESS) {
 224     cairo_surface_destroy(surf);
 225     return false;
 226   }
 227   return InstallCairoSurfacePixels(&bitmap_, surf, is_opaque);
 228 }
 229
 230 }  // namespace skia