Initial commit.

1 files changed, 263 insertions, 0 deletions

diff --git a/libdimension-png/png.c b/libdimension-png/png.c
new file mode 100644
index 0000000..750b5af
--- /dev/null
+++ b/libdimension-png/png.c
@@ -0,0 +1,263 @@
+/*************************************************************************
+ * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of Dimension.                                       *
+ *                                                                       *
+ * Dimension is free software; you can redistribute it and/or modify it  *
+ * under the terms of the GNU Lesser General Public License as published *
+ * by the Free Software Foundation; either version 3 of the License, or  *
+ * (at your option) any later version.                                   *
+ *                                                                       *
+ * Dimension is distributed in the hope that it will be useful, but      *
+ * WITHOUT ANY WARRANTY; without even the implied warranty of            *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU     *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+#include "dimension-png.h"
+#include <png.h>
+#include <setjmp.h>
+#include <arpa/inet.h>
+#include <stdlib.h>
+
+int
+dmnsn_png_write_canvas(const dmnsn_canvas *canvas, FILE *file)
+{
+  png_structp png_ptr;
+  png_infop info_ptr;
+  png_uint_32 width, height;
+  unsigned int x, y;
+  uint16_t *row = NULL;
+  dmnsn_pixel *pixel;
+
+  width = canvas->x;
+  height = canvas->y;
+
+  if (!file) return 1;
+
+  png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+  if (!png_ptr) return 1;
+
+  info_ptr = png_create_info_struct(png_ptr);
+  if (!info_ptr) {
+    png_destroy_write_struct(&png_ptr, NULL);
+    return 1;
+  }
+
+  if (setjmp(png_jmpbuf(png_ptr))) {
+    if (row) free(row);
+    png_destroy_write_struct(&png_ptr, &info_ptr);
+    return 1;
+  }
+
+  png_init_io(png_ptr, file);
+
+  png_set_IHDR(png_ptr, info_ptr, width, height, 16,
+               PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
+               PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+
+  png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr, PNG_sRGB_INTENT_ABSOLUTE);
+
+  png_set_invert_alpha(png_ptr);
+  png_write_info(png_ptr, info_ptr);
+
+  if (htonl(1) != 1) {
+    /* We are little-endian */
+    png_set_swap(png_ptr);
+  }
+
+  row = malloc(4*sizeof(uint16_t)*width);
+  if (!row) {
+    png_destroy_write_struct(&png_ptr, &info_ptr);
+    return 1;
+  }
+
+  for (y = 0; y < height; ++y) {
+    for (x = 0; x < width; ++x) {
+      /* Invert the rows.  PNG coordinates are fourth quadrant. */
+      pixel = canvas->pixels + (height - y - 1)*width + x;
+
+      row[4*x] = pixel->r;
+      row[4*x + 1] = pixel->g;
+      row[4*x + 2] = pixel->b;
+
+      if (pixel->a > pixel->t) {
+        row[4*x + 3] = pixel->a;
+      } else {
+        row[4*x + 3] = pixel->t;
+      }
+    }
+    png_write_row(png_ptr, (png_bytep)row);
+  }
+
+  png_write_end(png_ptr, info_ptr);
+
+  free(row);
+  png_destroy_write_struct(&png_ptr, &info_ptr);
+  return 0;
+}
+
+int
+dmnsn_png_read_canvas(dmnsn_canvas **canvas, FILE *file)
+{
+  png_byte header[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
+  png_structp png_ptr;
+  png_infop info_ptr;
+  png_uint_32 width, height, rowbytes;
+  int bit_depth, color_type, interlace_type, compression_type, filter_method;
+  png_bytep image = NULL;
+  png_bytep *row_pointers = NULL;
+  unsigned int x, y;
+  dmnsn_pixel *pixel;
+  png_bytep png_pixel;
+
+  /* Ensure that *canvas can always be deleted. */
+  *canvas = NULL;
+
+  if (!file) return 1;
+
+  fread(header, 1, 8, file);
+  if (png_sig_cmp(header, 0, 8)) return 1;
+
+  png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+  if (!png_ptr) return 1;
+
+  info_ptr = png_create_info_struct(png_ptr);
+  if (!info_ptr) {
+    png_destroy_read_struct(&png_ptr, NULL, NULL);
+    return 1;
+  }
+
+  if (setjmp(png_jmpbuf(png_ptr))) {
+    if (row_pointers) free(row_pointers);
+    if (image) free(image);
+    png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+    return 1;
+  }
+
+  png_init_io(png_ptr, file);
+  png_set_sig_bytes(png_ptr, 8);
+
+  png_read_info(png_ptr, info_ptr);
+
+  png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
+               &interlace_type, &compression_type, &filter_method);
+
+  /*
+   * - Convert paletted images to RGB.
+   * - Convert a tRNS chunk to an alpha channel
+   * - Convert grayscale to RGB
+   * - Invert the alpha channel
+   */
+  if (color_type == PNG_COLOR_TYPE_PALETTE) {
+    png_set_palette_to_rgb(png_ptr);
+  }
+  if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
+    png_set_tRNS_to_alpha(png_ptr);
+  }
+  if (color_type == PNG_COLOR_TYPE_GRAY
+      || color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
+          png_set_gray_to_rgb(png_ptr);
+  }
+  png_set_invert_alpha(png_ptr);
+
+  png_read_update_info(png_ptr, info_ptr);
+  rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+  image = malloc(rowbytes*height);
+  if (!image) {
+    png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+    return 1;
+  }
+
+  row_pointers = malloc(sizeof(png_bytep)*height);
+  if (!row_pointers) {
+    free(image);
+    png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+    return 1;
+  }
+
+  for (y = 0; y < height; ++y) {
+    row_pointers[y] = image + y*rowbytes;
+  }
+
+  png_read_image(png_ptr, row_pointers);
+
+  *canvas = dmnsn_new_canvas(width, height);
+  if (!*canvas) {
+    free(row_pointers);
+    free(image);
+    png_read_end(png_ptr, NULL);
+    png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+    return 1;
+  }
+
+  if (bit_depth == 16) {
+    if (color_type & PNG_COLOR_MASK_ALPHA) {
+      for (x = 0; x < width; ++x) {
+        for (y = 0; y < height; ++y) {
+          pixel = (*canvas)->pixels + (height - y - 1)*width + x;
+          png_pixel = image + 8*(y*width + x);
+
+          pixel->r = (png_pixel[0] << UINT16_C(8)) + png_pixel[1];
+          pixel->g = (png_pixel[2] << UINT16_C(8)) + png_pixel[3];
+          pixel->b = (png_pixel[4] << UINT16_C(8)) + png_pixel[5];
+          pixel->a = (png_pixel[6] << UINT16_C(8)) + png_pixel[7];
+          pixel->t = 0;
+        }
+      }
+    } else {
+      for (x = 0; x < width; ++x) {
+        for (y = 0; y < height; ++y) {
+          pixel = (*canvas)->pixels + (height - y - 1)*width + x;
+          png_pixel = image + 6*(y*width + x);
+
+          pixel->r = (png_pixel[0] << UINT16_C(8)) + png_pixel[1];
+          pixel->g = (png_pixel[2] << UINT16_C(8)) + png_pixel[3];
+          pixel->b = (png_pixel[4] << UINT16_C(8)) + png_pixel[5];
+          pixel->a = 0;
+          pixel->t = 0;
+        }
+      }
+    }
+  } else {
+    /* Bit depth is 8 */
+    if (color_type & PNG_COLOR_MASK_ALPHA) {
+      for (x = 0; x < width; ++x) {
+        for (y = 0; y < height; ++y) {
+          pixel = (*canvas)->pixels + (height - y - 1)*width + x;
+          png_pixel = image + 4*(y*width + x);
+
+          pixel->r = png_pixel[0] << UINT16_C(8);
+          pixel->g = png_pixel[1] << UINT16_C(8);
+          pixel->b = png_pixel[2] << UINT16_C(8);
+          pixel->a = png_pixel[3] << UINT16_C(8);
+          pixel->t = 0;
+        }
+      }
+    } else {
+      for (x = 0; x < width; ++x) {
+        for (y = 0; y < height; ++y) {
+          pixel = (*canvas)->pixels + (height - y - 1)*width + x;
+          png_pixel = image + 3*(y*width + x);
+
+          pixel->r = png_pixel[0] << UINT16_C(8);
+          pixel->g = png_pixel[1] << UINT16_C(8);
+          pixel->b = png_pixel[2] << UINT16_C(8);
+          pixel->a = 0;
+          pixel->t = 0;
+        }
+      }
+    }
+  }
+
+  free(row_pointers);
+  free(image);
+  png_read_end(png_ptr, NULL);
+  png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+  return 0;
+}