lib/art/art_render.h

   1 /*
   2  * art_render.h: Modular rendering architecture.
   3  *
   4  * Libart_LGPL - library of basic graphic primitives
   5  * Copyright (C) 2000 Raph Levien
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Library General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Library General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Library General Public
  18  * License along with this library; if not, write to the
  19  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  20  * Boston, MA 02111-1307, USA.
  21  */
  22
  23 #ifndef __ART_RENDER_H__
  24 #define __ART_RENDER_H__
  25
  26 #ifdef LIBART_COMPILATION
  27 #include "art_alphagamma.h"
  28 #else
  29 #include "art_alphagamma.h"
  30 #endif
  31
  32 #ifdef __cplusplus
  33 extern "C" {
  34 #endif /* __cplusplus */
  35
  36 /* Render object */
  37
  38 #ifndef ART_MAX_DEPTH
  39 #define ART_MAX_DEPTH 16
  40 #endif
  41
  42 #if ART_MAX_DEPTH == 16
  43 typedef art_u16 ArtPixMaxDepth;
  44 #define ART_PIX_MAX_FROM_8(x) ((x) | ((x) << 8))
  45 #define ART_PIX_8_FROM_MAX(x) (((x) + 0x80 - (((x) + 0x80) >> 8)) >> 8)
  46 #else
  47 #if ART_MAX_DEPTH == 8
  48 typedef art_u8 ArtPixMaxDepth;
  49 #define ART_PIX_MAX_FROM_8(x) (x)
  50 #define ART_PIX_8_FROM_MAX(x) (x)
  51 #else
  52 #error ART_MAX_DEPTH must be either 8 or 16
  53 #endif
  54 #endif
  55
  56 #define ART_MAX_CHAN 16
  57
  58 typedef struct _ArtRender ArtRender;
  59 typedef struct _ArtRenderCallback ArtRenderCallback;
  60 typedef struct _ArtRenderMaskRun ArtRenderMaskRun;
  61 typedef struct _ArtImageSource ArtImageSource;
  62 typedef struct _ArtMaskSource ArtMaskSource;
  63
  64 typedef enum {
  65   ART_ALPHA_NONE      = 0,
  66   ART_ALPHA_SEPARATE  = 1,
  67   ART_ALPHA_PREMUL    = 2
  68 } ArtAlphaType;
  69
  70 typedef enum {
  71   ART_COMPOSITE_NORMAL,
  72   ART_COMPOSITE_MULTIPLY,
  73   /* todo: more */
  74   ART_COMPOSITE_CUSTOM
  75 } ArtCompositingMode;
  76
  77 #define ART_IMAGE_SOURCE_CAN_CLEAR 1
  78 #define ART_IMAGE_SOURCE_CAN_COMPOSITE 2
  79
  80 struct _ArtRenderMaskRun {
  81   int x;
  82   int alpha;
  83 };
  84
  85 struct _ArtRenderCallback {
  86   void (*render) (ArtRenderCallback *self, ArtRender *render,
  87                   art_u8 *dest, int y);
  88   void (*done) (ArtRenderCallback *self, ArtRender *render);
  89 };
  90
  91 struct _ArtImageSource {
  92   ArtRenderCallback super;
  93   void (*negotiate) (ArtImageSource *self, ArtRender *render,
  94                      int *p_flags,
  95                      int *p_buf_depth, ArtAlphaType *p_alpha_type);
  96 };
  97
  98 struct _ArtMaskSource {
  99   ArtRenderCallback super;
 100   int (*can_drive) (ArtMaskSource *self, ArtRender *render);
 101   /* For each mask source, ::prepare() is invoked if it is not
 102      a driver, or ::invoke_driver() if it is. */
 103   void (*invoke_driver) (ArtMaskSource *self, ArtRender *render);
 104   void (*prepare) (ArtMaskSource *self, ArtRender *render, art_boolean first);
 105 };
 106
 107 struct _ArtRender {
 108   /* parameters of destination image */
 109   int x0, y0;
 110   int x1, y1;
 111   art_u8 *pixels;
 112   int rowstride;
 113   int n_chan;
 114   int depth;
 115   ArtAlphaType alpha_type;
 116
 117   art_boolean clear;
 118   ArtPixMaxDepth clear_color[ART_MAX_CHAN + 1];
 119   art_u32 opacity; /* [0..0x10000] */
 120
 121   ArtCompositingMode compositing_mode;
 122
 123   ArtAlphaGamma *alphagamma;
 124
 125   art_u8 *alpha_buf;
 126
 127   /* parameters of intermediate buffer */
 128   int buf_depth;
 129   ArtAlphaType buf_alpha;
 130   art_u8 *image_buf;
 131
 132   /* driving alpha scanline data */
 133   /* A "run" is a contiguous sequence of x values with the same alpha value. */
 134   int n_run;
 135   ArtRenderMaskRun *run;
 136
 137   /* A "span" is a contiguous sequence of x values with non-zero alpha. */
 138   int n_span;
 139   int *span_x;
 140
 141   art_boolean need_span;
 142 };
 143
 144 ArtRender *
 145 art_render_new (int x0, int y0, int x1, int y1,
 146                 art_u8 *pixels, int rowstride,
 147                 int n_chan, int depth, ArtAlphaType alpha_type,
 148                 ArtAlphaGamma *alphagamma);
 149
 150 void
 151 art_render_invoke (ArtRender *render);
 152
 153 void
 154 art_render_clear (ArtRender *render, const ArtPixMaxDepth *clear_color);
 155
 156 void
 157 art_render_clear_rgb (ArtRender *render, art_u32 clear_rgb);
 158
 159 void
 160 art_render_mask_solid (ArtRender *render, int opacity);
 161
 162 void
 163 art_render_image_solid (ArtRender *render, ArtPixMaxDepth *color);
 164
 165 /* The next two functions are for custom mask sources only. */
 166 void
 167 art_render_add_mask_source (ArtRender *render, ArtMaskSource *mask_source);
 168
 169 void
 170 art_render_invoke_callbacks (ArtRender *render, art_u8 *dest, int y);
 171
 172 /* The following function is for custom image sources only. */
 173 void
 174 art_render_add_image_source (ArtRender *render, ArtImageSource *image_source);
 175
 176 #ifdef __cplusplus
 177 }
 178 #endif /* __cplusplus */
 179
 180 #endif /* __ART_RENDER_H__ */
 181