cairo-rendering.c

   1 /*******************************************************************************
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   3 **      10        20        30        40        50        60        70        80
   4 **
   5 ** file:
   6 **    cairo-rendering.c
   7 **
   8 ** author:
   9 **    Mirco "MacSlow" Mueller <macslow@bangang.de>
  10 **
  11 ** copyright (C) Mirco Mueller, July 2006, placed under the terms of the LGPL
  12 **
  13 *******************************************************************************/
  14
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17 #include <math.h>
  18
  19 #include "geometry.h"
  20 #include "cairo-rendering.h"
  21
  22 cairo_t*
  23 create_cairo_context (int  iWidth,
  24                                           int iHeight,
  25                                           int iChannels,
  26                                           cairo_surface_t** pSurface,
  27                                           unsigned char** pucBuffer)
  28 {
  29         cairo_t* pCairoContext = NULL;
  30
  31         /* create cairo-surface/context to act as OpenGL-texture source */
  32         *pucBuffer = calloc (iChannels * iWidth * iHeight, sizeof (unsigned char));
  33         if (!*pucBuffer)
  34         {
  35         printf ("create_cairo_context() - Couldn't allocate surface-buffer\n");
  36         return NULL;
  37         }
  38
  39         *pSurface = cairo_image_surface_create_for_data (*pucBuffer,
  40                                                                                                          CAIRO_FORMAT_ARGB32,
  41                                                                                                          iWidth,
  42                                                                                                          iHeight,
  43                                                                                                          iChannels * iWidth);
  44         if (cairo_surface_status (*pSurface) != CAIRO_STATUS_SUCCESS)
  45         {
  46                 free (*pucBuffer);
  47         printf ("create_cairo_context() - Couldn't create surface\n");
  48         return NULL;
  49         }
  50
  51         pCairoContext = cairo_create (*pSurface);
  52         if (cairo_status (pCairoContext) != CAIRO_STATUS_SUCCESS)
  53         {
  54                 free (*pucBuffer);
  55         printf ("create_cairo_context() - Couldn't create context\n");
  56         return NULL;
  57         }
  58
  59         return pCairoContext;
  60 }
  61
  62 void
  63 render_curve (cairo_t* pCairoContext,
  64                           int iWidth,
  65                           int iHeight,
  66                           Line* pLineOne,
  67                           Line* pLineTwo,
  68                           double fLineWidth)
  69 {
  70         if (pLineOne == NULL || pLineTwo == NULL)
  71                 return;
  72
  73         cairo_save (pCairoContext);
  74         cairo_set_operator (pCairoContext, CAIRO_OPERATOR_OVER);
  75         cairo_scale (pCairoContext, (double) iWidth / 1.0f, (double) iHeight / 1.0f);
  76         cairo_set_source_rgba (pCairoContext, 0.0f, 1.0f, 0.0f, 1.0f);
  77         cairo_paint (pCairoContext);
  78
  79         cairo_set_source_rgba (pCairoContext, 0.0f, 0.0f, 0.0f, 1.0f);
  80         cairo_set_line_cap (pCairoContext, CAIRO_LINE_CAP_ROUND);
  81         cairo_set_line_width (pCairoContext, fLineWidth);
  82         cairo_move_to (pCairoContext, pLineOne->start.fX, pLineOne->start.fY);
  83         cairo_curve_to (pCairoContext,
  84                                         pLineOne->end.fX,
  85                                         pLineOne->end.fY,
  86                                         pLineTwo->start.fX,
  87                                         pLineTwo->start.fY,
  88                                         pLineTwo->end.fX,
  89                                         pLineTwo->end.fY);
  90         cairo_stroke (pCairoContext);
  91         cairo_restore (pCairoContext);
  92 }