libgimpcolor/gimpcairo.h

   1 /* LIBGIMP - The GIMP Library
   2  * Copyright (C) 1995-1997 Peter Mattis and Spencer Kimball
   3  *
   4  * gimpcairo.h
   5  * Copyright (C) 2007      Sven Neumann <sven@gimp.org>
   6  *               2010-2012 Michael Natterer <mitch@gimp.org>
   7  *
   8  * This library is free software: you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 3 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library.  If not, see
  20  * <https://www.gnu.org/licenses/>.
  21  */
  22
  23 #ifndef __GIMP_CAIRO_H__
  24 #define __GIMP_CAIRO_H__
  25
  26
  27 void              gimp_cairo_set_source_rgb        (cairo_t         *cr,
  28                                                     const GimpRGB   *color);
  29 void              gimp_cairo_set_source_rgba       (cairo_t         *cr,
  30                                                     const GimpRGB   *color);
  31
  32 cairo_pattern_t * gimp_cairo_checkerboard_create   (cairo_t         *cr,
  33                                                     gint             size,
  34                                                     const GimpRGB   *light,
  35                                                     const GimpRGB   *dark);
  36
  37 const Babl      * gimp_cairo_surface_get_format    (cairo_surface_t *surface);
  38 GeglBuffer      * gimp_cairo_surface_create_buffer (cairo_surface_t *surface);
  39
  40
  41 /*  some useful macros for writing directly to a Cairo surface  */
  42
  43 /**
  44  * GIMP_CAIRO_RGB24_SET_PIXEL:
  45  * @d: pointer to the destination buffer
  46  * @r: red component
  47  * @g: green component
  48  * @b: blue component
  49  *
  50  * Sets a single pixel in an Cairo image surface in %CAIRO_FORMAT_RGB24.
  51  *
  52  * Since: 2.6
  53  **/
  54 #if G_BYTE_ORDER == G_LITTLE_ENDIAN
  55 #define GIMP_CAIRO_RGB24_SET_PIXEL(d, r, g, b) \
  56   G_STMT_START { d[0] = (b);  d[1] = (g);  d[2] = (r); } G_STMT_END
  57 #else
  58 #define GIMP_CAIRO_RGB24_SET_PIXEL(d, r, g, b) \
  59   G_STMT_START { d[1] = (r);  d[2] = (g);  d[3] = (b); } G_STMT_END
  60 #endif
  61
  62
  63 /**
  64  * GIMP_CAIRO_RGB24_GET_PIXEL:
  65  * @s: pointer to the source buffer
  66  * @r: red component
  67  * @g: green component
  68  * @b: blue component
  69  *
  70  * Gets a single pixel from a Cairo image surface in %CAIRO_FORMAT_RGB24.
  71  *
  72  * Since: 2.8
  73  **/
  74 #if G_BYTE_ORDER == G_LITTLE_ENDIAN
  75 #define GIMP_CAIRO_RGB24_GET_PIXEL(s, r, g, b) \
  76   G_STMT_START { (b) = s[0]; (g) = s[1]; (r) = s[2]; } G_STMT_END
  77 #else
  78 #define GIMP_CAIRO_RGB24_GET_PIXEL(s, r, g, b) \
  79   G_STMT_START { (r) = s[1]; (g) = s[2]; (b) = s[3]; } G_STMT_END
  80 #endif
  81
  82
  83 /**
  84  * GIMP_CAIRO_ARGB32_SET_PIXEL:
  85  * @d: pointer to the destination buffer
  86  * @r: red component, not pre-multiplied
  87  * @g: green component, not pre-multiplied
  88  * @b: blue component, not pre-multiplied
  89  * @a: alpha component
  90  *
  91  * Sets a single pixel in an Cairo image surface in %CAIRO_FORMAT_ARGB32.
  92  *
  93  * Since: 2.6
  94  **/
  95 #if G_BYTE_ORDER == G_LITTLE_ENDIAN
  96 #define GIMP_CAIRO_ARGB32_SET_PIXEL(d, r, g, b, a) \
  97   G_STMT_START {                                   \
  98     const guint tr = (a) * (r) + 0x80;             \
  99     const guint tg = (a) * (g) + 0x80;             \
 100     const guint tb = (a) * (b) + 0x80;             \
 101     (d)[0] = (((tb) >> 8) + (tb)) >> 8;            \
 102     (d)[1] = (((tg) >> 8) + (tg)) >> 8;            \
 103     (d)[2] = (((tr) >> 8) + (tr)) >> 8;            \
 104     (d)[3] = (a);                                  \
 105   } G_STMT_END
 106 #else
 107 #define GIMP_CAIRO_ARGB32_SET_PIXEL(d, r, g, b, a) \
 108   G_STMT_START {                                   \
 109     const guint tr = (a) * (r) + 0x80;             \
 110     const guint tg = (a) * (g) + 0x80;             \
 111     const guint tb = (a) * (b) + 0x80;             \
 112     (d)[0] = (a);                                  \
 113     (d)[1] = (((tr) >> 8) + (tr)) >> 8;            \
 114     (d)[2] = (((tg) >> 8) + (tg)) >> 8;            \
 115     (d)[3] = (((tb) >> 8) + (tb)) >> 8;            \
 116   } G_STMT_END
 117 #endif
 118
 119
 120 /**
 121  * GIMP_CAIRO_ARGB32_GET_PIXEL:
 122  * @s: pointer to the source buffer
 123  * @r: red component, not pre-multiplied
 124  * @g: green component, not pre-multiplied
 125  * @b: blue component, not pre-multiplied
 126  * @a: alpha component
 127  *
 128  * Gets a single pixel from a Cairo image surface in %CAIRO_FORMAT_ARGB32.
 129  *
 130  * Since: 2.8
 131  **/
 132 #if G_BYTE_ORDER == G_LITTLE_ENDIAN
 133 #define GIMP_CAIRO_ARGB32_GET_PIXEL(s, r, g, b, a) \
 134   G_STMT_START {                                   \
 135     const guint tb = (s)[0];                       \
 136     const guint tg = (s)[1];                       \
 137     const guint tr = (s)[2];                       \
 138     const guint ta = (s)[3];                       \
 139     (r) = (tr << 8) / (ta + 1);                    \
 140     (g) = (tg << 8) / (ta + 1);                    \
 141     (b) = (tb << 8) / (ta + 1);                    \
 142     (a) = ta;                                      \
 143   } G_STMT_END
 144 #else
 145 #define GIMP_CAIRO_ARGB32_GET_PIXEL(s, r, g, b, a) \
 146   G_STMT_START {                                   \
 147     const guint ta = (s)[0];                       \
 148     const guint tr = (s)[1];                       \
 149     const guint tg = (s)[2];                       \
 150     const guint tb = (s)[3];                       \
 151     (r) = (tr << 8) / (ta + 1);                    \
 152     (g) = (tg << 8) / (ta + 1);                    \
 153     (b) = (tb << 8) / (ta + 1);                    \
 154     (a) = ta;                                      \
 155   } G_STMT_END
 156 #endif
 157
 158
 159 #endif /* __GIMP_CAIRO_H__ */