scale.c

   1 /*
   2  *  Copyright (C) 2008  Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
   3  *
   4  *  This program is free software; you can redistribute it and/or modify
   5  *  it under the terms of the GNU General Public License as published by
   6  *  the Free Software Foundation; either version 2 of the License, or
   7  *  (at your option) any later version.
   8  *
   9  *  This program is distributed in the hope that it will be useful,
  10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *  GNU General Public License for more details.
  13  *
  14  *  You should have received a copy of the GNU General Public License along
  15  *  with this program; if not, write to the Free Software Foundation, Inc.,
  16  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <cairo.h>
  23 #include <SDL.h>
  24 #include <SDL_image.h>
  25
  26 cairo_surface_t *
  27 CairoFromSDL (SDL_Surface *surface)
  28 {
  29   return cairo_image_surface_create_for_data (surface->pixels,
  30                                               CAIRO_FORMAT_ARGB32,
  31                                               surface->w, surface->h,
  32                                               surface->pitch);
  33 }
  34
  35 SDL_Surface *
  36 CairoToSDL (cairo_surface_t *surface)
  37 {
  38   return SDL_CreateRGBSurfaceFrom (cairo_image_surface_get_data (surface),
  39                                    cairo_image_surface_get_width (surface),
  40                                    cairo_image_surface_get_height (surface),
  41                                    32,
  42                                    cairo_image_surface_get_stride (surface),
  43                                    0x00ff0000, 0x0000ff00, 0x000000ff,
  44                                    0xff000000);
  45 }
  46
  47 SDL_Surface *
  48 CairoTarget (SDL_Surface *image, double scale)
  49 {
  50   unsigned char *data = NULL;
  51   cairo_surface_t *surface = NULL;
  52   cairo_t *ctx = NULL;
  53   cairo_surface_t *source;
  54   SDL_Surface *dest;
  55   int w, h;
  56   w = image->w * scale;
  57   h = image->h * scale;
  58   data = malloc (w * h * 4);
  59   surface = cairo_image_surface_create_for_data (data, CAIRO_FORMAT_ARGB32,
  60                                                  w, h, w * 4);
  61   ctx = cairo_create (surface);
  62   cairo_scale (ctx, scale, scale);
  63   source = CairoFromSDL (image);
  64   cairo_set_source_surface (ctx, source, 0, 0);
  65   cairo_paint (ctx);
  66   cairo_surface_destroy (source);
  67   dest = CairoToSDL (surface);
  68   cairo_surface_destroy (surface);
  69   cairo_destroy (ctx);
  70   return dest;
  71 }
  72
  73 SDL_Surface *
  74 CairoScale (SDL_Surface *image, double scale)
  75 {
  76   SDL_Surface *newfmt;
  77   SDL_Surface *slice;
  78   SDL_Surface *scaled_image;
  79   newfmt = SDL_CreateRGBSurface (SDL_SWSURFACE, 1, 1,
  80                                  32,
  81                                  0x00ff0000,
  82                                  0x0000ff00,
  83                                  0x000000ff,
  84                                  0xff000000);
  85   slice = SDL_ConvertSurface (image, newfmt->format, SDL_SWSURFACE);
  86   SDL_FreeSurface (newfmt);
  87   scaled_image = CairoTarget (slice, scale);
  88   SDL_FreeSurface (slice);
  89   return scaled_image;
  90 }