operations/common/linear-gradient.c

   1 /* This file is an image processing operation for GEGL
   2  *
   3  * GEGL is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU Lesser General Public
   5  * License as published by the Free Software Foundation; either
   6  * version 3 of the License, or (at your option) any later version.
   7  *
   8  * GEGL is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * Lesser General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public
  14  * License along with GEGL; if not, see <https://www.gnu.org/licenses/>.
  15  *
  16  * Copyright 2008 Øyvind Kolås <pippin@gimp.org>
  17  *           2013 Daniel Sabo
  18  */
  19
  20 #include "config.h"
  21 #include <glib/gi18n-lib.h>
  22
  23 #ifdef GEGL_PROPERTIES
  24
  25 property_double (start_x, _("X1"), 25.0)
  26     ui_meta("unit", "pixel-coordinate")
  27     ui_meta("axis", "x")
  28
  29 property_double (start_y, _("Y1"), 25.0)
  30     ui_meta("unit", "pixel-coordinate")
  31     ui_meta("axis", "y")
  32
  33 property_double (end_x, _("X2"), 150.0)
  34     ui_meta("unit", "pixel-coordinate")
  35     ui_meta("axis", "x")
  36
  37 property_double (end_y, _("Y2"), 150.0)
  38     ui_meta ("unit", "pixel-coordinate")
  39     ui_meta ("axis", "y")
  40
  41 property_color (start_color, _("Start Color"), "black")
  42     description (_("The color at (x1, y1)"))
  43     ui_meta ("role", "color-primary")
  44
  45 property_color  (end_color, _("End Color"), "white")
  46     description (_("The color at (x2, y2)"))
  47     ui_meta     ("role", "color-secondary")
  48
  49 #else
  50
  51 #define GEGL_OP_POINT_RENDER
  52 #define GEGL_OP_NAME     linear_gradient
  53 #define GEGL_OP_C_SOURCE linear-gradient.c
  54
  55 #include "gegl-op.h"
  56
  57 static void
  58 prepare (GeglOperation *operation)
  59 {
  60   gegl_operation_set_format (operation, "output", babl_format ("R'G'B'A float"));
  61 }
  62
  63 static GeglRectangle
  64 get_bounding_box (GeglOperation *operation)
  65 {
  66   return gegl_rectangle_infinite_plane ();
  67 }
  68
  69 static gboolean
  70 process (GeglOperation       *operation,
  71          void                *out_buf,
  72          glong                n_pixels,
  73          const GeglRectangle *roi,
  74          gint                 level)
  75 {
  76   GeglProperties *o = GEGL_PROPERTIES (operation);
  77   gfloat         *out_pixel = out_buf;
  78   gfloat          color1[4], color2[4], length, dx, dy;
  79   gfloat factor = 1.0/(1 << level);
  80
  81   dx = (o->end_x - o->start_x) * factor;
  82   dy = (o->end_y - o->start_y) * factor;
  83
  84   length = dx * dx + dy * dy;
  85
  86   if (GEGL_FLOAT_IS_ZERO (length))
  87     {
  88       memset (out_buf, 0, n_pixels * sizeof(float) * 4);
  89     }
  90   else
  91     {
  92       gfloat vec0 = dx / length;
  93       gfloat vec1 = dy / length;
  94       gint x, y;
  95
  96       gegl_color_get_pixel (o->start_color, babl_format ("R'G'B'A float"), color1);
  97       gegl_color_get_pixel (o->end_color, babl_format ("R'G'B'A float"), color2);
  98
  99       for (y = roi->y; y < roi->y + roi->height; ++y)
 100         {
 101           for (x = roi->x; x < roi->x + roi->width; ++x)
 102             {
 103               gint c;
 104               gfloat v = vec0 * (x - o->start_x * factor) + vec1 * (y - o->start_y * factor);
 105
 106               if (v > 1.0f - GEGL_FLOAT_EPSILON)
 107                 v = 1.0f;
 108               if (v < 0.0f + GEGL_FLOAT_EPSILON)
 109                 v = 0.0f;
 110
 111               for (c = 0; c < 4; c++)
 112                 out_pixel[c] = color2[c] * v + color1[c] * (1.0f - v);
 113
 114               out_pixel += 4;
 115             }
 116         }
 117     }
 118
 119   return  TRUE;
 120 }
 121
 122 static void
 123 gegl_op_class_init (GeglOpClass *klass)
 124 {
 125   GeglOperationClass            *operation_class;
 126   GeglOperationPointRenderClass *point_render_class;
 127
 128   operation_class = GEGL_OPERATION_CLASS (klass);
 129   point_render_class = GEGL_OPERATION_POINT_RENDER_CLASS (klass);
 130
 131   point_render_class->process = process;
 132   operation_class->get_bounding_box = get_bounding_box;
 133   operation_class->prepare = prepare;
 134
 135   gegl_operation_class_set_keys (operation_class,
 136     "name",               "gegl:linear-gradient",
 137     "title",              _("Linear Gradient"),
 138     "categories",         "render:gradient",
 139     "position-dependent", "true",
 140     "reference-hash",     "f53de20993b50915061e67e69ab006f4",
 141     "reference-hashB",    "7c514dcf1a0d580fe52476084246a0f4",
 142     "description" , _("Linear gradient renderer"),
 143     NULL);
 144 }
 145
 146 #endif