src/lib/pngwrite.c 1.2

Index: src/lib/pngwrite.c
===================================================================
RCS file: /projects/compbio/cvsroot/kent/src/lib/pngwrite.c,v
retrieving revision 1.1
retrieving revision 1.2
diff -b -B -U 1000000 -r1.1 -r1.2
--- src/lib/pngwrite.c	5 Aug 2009 23:34:31 -0000	1.1
+++ src/lib/pngwrite.c	20 Aug 2009 21:34:44 -0000	1.2
@@ -1,114 +1,114 @@
 /* pngwrite.c - write out a memGfx to a PNG file, using the reference library libpng */
 /* (libpng is available from sourceforge and included in many open source distros,
  *  has a wide-open license intended to encourage usage of the PNG format, and the lib
  *  has been under development and testing for 14 years -- http://libpng.org/) */
 
 #ifdef USE_PNG
 
 #include "common.h"
 #include "memgfx.h"
-#ifdef SETJMP_H
-//.crap!;
-#endif
+#ifdef _SETJMP_H
+//.!$ simulate syntax error like the distro /usr/include/pngconf.h does when setjmp.h has already been included.  currently common.h includes it.
+#endif//def _SETJMP_H
 #include "png.h"
 
 static char const rcsid[] = "$Id$";
 
 static void pngAbort(png_structp png, png_const_charp errorMessage)
 /* type png_error wrapper around errAbort */
 {
 errAbort((char *)errorMessage);
 }
 
 static void pngWarn(png_structp png, png_const_charp warningMessage)
 /* type png_error wrapper around warn */
 {
 warn((char *)warningMessage);
 }
 
-boolean mgSaveToPng(FILE *png_file, struct memGfx *mg, boolean useAlpha)
+boolean mgSaveToPng(FILE *png_file, struct memGfx *mg, boolean useTransparency)
 /* Save PNG to an already open file.
- * If useAlpha, then the first color in memgfx's colormap/palette is
+ * If useTransparency, then the first color in memgfx's colormap/palette is
  * assumed to be the image background color, and pixels of that color
  * are made transparent. */
 /* Reference: http://libpng.org/pub/png/libpng-1.2.5-manual.html */
 {
 if (!png_file || !mg)
-    errAbort("mgSaveToPng: caller screwed up: png_file=[%lld], mg=[%lld]",
+    errAbort("mgSaveToPng: called with a NULL: png_file=[%lld], mg=[%lld]",
 	     (long long int)png_file, (long long int)mg);
 png_structp png = png_create_write_struct(PNG_LIBPNG_VER_STRING,
 					  NULL, // don't need pointer to data for err/warn handlers
 					  pngAbort, pngWarn);
 if (!png)
     {
     errAbort("png_write_struct failed");
     return FALSE;
     }
 png_infop info = png_create_info_struct(png);
 if (!info)
     {
     errAbort("png create_info_struct failed");
     png_destroy_write_struct(&png, NULL);
     return FALSE;
     }
 
 // If setjmp returns nonzero, it means png_error is returning control here.
 // But that should not happen because png_error should call pngAbort which calls errAbort.
 if (setjmp(png_jmpbuf(png)))
     {
     png_destroy_write_struct(&png, &info);
     fclose(png_file);
     errAbort("pngwrite: setjmp nonzero.  "
 	     "why didn't png_error..pngAbort..errAbort stop execution before this errAbort?");
     return FALSE;
     }
 
 // Configure PNG output params:
 png_init_io(png, png_file);
 png_set_IHDR(png, info, mg->width, mg->height, 8, // 8=bit_depth
 	     PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
 	     PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
 png_set_PLTE(png, info,
 	     (png_color *)(mg->colorMap), // png_color is same as struct rgbColor!
 	     mg->colorsUsed);
-if (useAlpha)
+if (useTransparency)
     {
     // First palette color is assumed to be background/transparent, so
     // that's the only one we need in the parallel array opacities[].
     png_byte opacities[] = {0};
     int num_opacities = ArraySize(opacities);
     png_color_16p nonPalette_opacities_values = NULL; // n/a for us, we're using palette
     png_set_tRNS(png, info, opacities, num_opacities, nonPalette_opacities_values);
     }
 
 // Write header/params, write pixels, close and clean up.
 // PNG wants a 2D array of pointers to byte offsets into palette/colorMap.
 // mg has a 1D array of byte offsets.  Make row pointers for PNG:
 png_byte **row_pointers = needMem(mg->height * sizeof(png_byte *));
 int i;
 for (i = 0;  i < mg->height;  i++)
     row_pointers[i] = &(mg->pixels[i*mg->width]);
 png_set_rows(png, info, row_pointers);
 png_write_png(png, info, PNG_TRANSFORM_IDENTITY, // no transform
 	      NULL); // unused as of PNG 1.2
 png_destroy_write_struct(&png, &info);
 return TRUE;
 }
 
-void mgSavePng(struct memGfx *mg, char *filename, boolean useAlpha)
+void mgSavePng(struct memGfx *mg, char *filename, boolean useTransparency)
 /* Save memory bitmap to filename as a PNG.
- * If useAlpha, then the first color in memgfx's colormap/palette is
+ * If useTransparency, then the first color in memgfx's colormap/palette is
  * assumed to be the image background color, and pixels of that color
  * are made transparent. */
 {
 FILE *pngFile = mustOpen(filename, "wb");
-if (!mgSaveToPng(pngFile, mg, useAlpha))
+if (!mgSaveToPng(pngFile, mg, useTransparency))
     {
     remove(filename);
     errAbort("Couldn't save %s", filename);
     }
 if (fclose(pngFile) != 0)
     errnoAbort("fclose failed");
 }
 
 #endif//def USE_PNG