moving trunk for module inkscape

(bzr r1)

1 files changed, 205 insertions, 0 deletions

diff --git a/src/helper/png-write.cpp b/src/helper/png-write.cpp
new file mode 100644
index 000000000..21eca1efa
--- /dev/null
+++ b/src/helper/png-write.cpp
@@ -0,0 +1,205 @@
+#define __SP_PNG_WRITE_C__
+
+/*
+ * PNG file format utilities
+ *
+ * Authors:
+ *   Lauris Kaplinski <lauris@kaplinski.com>
+ *   Whoever wrote this example in libpng documentation
+ *
+ * Copyright (C) 1999-2002 authors
+ *
+ * Released under GNU GPL, read the file 'COPYING' for more information
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <glib/gmessages.h>
+#include <png.h>
+#include "png-write.h"
+#include "io/sys.h"
+
+/* This is an example of how to use libpng to read and write PNG files.
+ * The file libpng.txt is much more verbose then this.  If you have not
+ * read it, do so first.  This was designed to be a starting point of an
+ * implementation.  This is not officially part of libpng, and therefore
+ * does not require a copyright notice.
+ *
+ * This file does not currently compile, because it is missing certain
+ * parts, like allocating memory to hold an image.  You will have to
+ * supply these parts to get it to compile.  For an example of a minimal
+ * working PNG reader/writer, see pngtest.c, included in this distribution.
+ */
+
+/* write a png file */
+
+typedef struct SPPNGBD {
+	const guchar *px;
+	int rowstride;
+} SPPNGBD;
+
+static int
+sp_png_get_block_stripe (const guchar **rows, int row, int num_rows, void *data)
+{
+	SPPNGBD *bd = (SPPNGBD *) data;
+
+	for (int r = 0; r < num_rows; r++) {
+		rows[r] = bd->px + (row + r) * bd->rowstride;
+	}
+
+	return num_rows;
+}
+
+int
+sp_png_write_rgba (const gchar *filename, const guchar *px, int width, int height, int rowstride)
+{
+	SPPNGBD bd;
+
+	bd.px = px;
+	bd.rowstride = rowstride;
+
+	return sp_png_write_rgba_striped (filename, width, height, sp_png_get_block_stripe, &bd);
+}
+
+int
+sp_png_write_rgba_striped (const gchar *filename, int width, int height,
+			   int (* get_rows) (const guchar **rows, int row, int num_rows, void *data),
+			   void *data)
+{
+	FILE *fp;
+	png_structp png_ptr;
+	png_infop info_ptr;
+	png_color_8 sig_bit;
+	png_text text_ptr[3];
+	png_uint_32 r;
+
+	g_return_val_if_fail (filename != NULL, FALSE);
+
+	/* open the file */
+
+	Inkscape::IO::dump_fopen_call(filename, "M");
+	fp = Inkscape::IO::fopen_utf8name(filename, "wb");
+	g_return_val_if_fail (fp != NULL, FALSE);
+
+	/* Create and initialize the png_struct with the desired error handler
+	 * functions.  If you want to use the default stderr and longjump method,
+	 * you can supply NULL for the last three parameters.  We also check that
+	 * the library version is compatible with the one used at compile time,
+	 * in case we are using dynamically linked libraries.  REQUIRED.
+	 */
+	png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+
+	if (png_ptr == NULL) {
+		fclose(fp);
+		return FALSE;
+	}
+
+	/* Allocate/initialize the image information data.  REQUIRED */
+	info_ptr = png_create_info_struct(png_ptr);
+	if (info_ptr == NULL) {
+		fclose(fp);
+		png_destroy_write_struct(&png_ptr, NULL);
+		return FALSE;
+	}
+
+	/* Set error handling.  REQUIRED if you aren't supplying your own
+	 * error hadnling functions in the png_create_write_struct() call.
+	 */
+	if (setjmp(png_ptr->jmpbuf)) {
+		/* If we get here, we had a problem reading the file */
+		fclose(fp);
+		png_destroy_write_struct(&png_ptr, &info_ptr);
+		return FALSE;
+	}
+
+	/* set up the output control if you are using standard C streams */
+	png_init_io(png_ptr, fp);
+
+	/* Set the image information here.  Width and height are up to 2^31,
+	 * bit_depth is one of 1, 2, 4, 8, or 16, but valid values also depend on
+	 * the color_type selected. color_type is one of PNG_COLOR_TYPE_GRAY,
+	 * PNG_COLOR_TYPE_GRAY_ALPHA, PNG_COLOR_TYPE_PALETTE, PNG_COLOR_TYPE_RGB,
+	 * or PNG_COLOR_TYPE_RGB_ALPHA.  interlace is either PNG_INTERLACE_NONE or
+	 * PNG_INTERLACE_ADAM7, and the compression_type and filter_type MUST
+	 * currently be PNG_COMPRESSION_TYPE_BASE and PNG_FILTER_TYPE_BASE. REQUIRED
+	 */
+	png_set_IHDR(png_ptr, info_ptr,
+		     width,
+		     height,
+		     8, /* bit_depth */
+		     PNG_COLOR_TYPE_RGB_ALPHA,
+		     PNG_INTERLACE_NONE,
+		     PNG_COMPRESSION_TYPE_BASE,
+		     PNG_FILTER_TYPE_BASE);
+
+	/* otherwise, if we are dealing with a color image then */
+	sig_bit.red = 8;
+	sig_bit.green = 8;
+	sig_bit.blue = 8;
+	/* if the image has an alpha channel then */
+	sig_bit.alpha = 8;
+	png_set_sBIT(png_ptr, info_ptr, &sig_bit);
+
+	/* Made by Inkscape comment */
+	text_ptr[0].key = "Software";
+	text_ptr[0].text = "www.inkscape.org";
+	text_ptr[0].compression = PNG_TEXT_COMPRESSION_NONE;
+	png_set_text(png_ptr, info_ptr, text_ptr, 1);
+
+	/* other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs, */
+	/* note that if sRGB is present the cHRM chunk must be ignored
+	 * on read and must be written in accordance with the sRGB profile */
+
+	/* Write the file header information.  REQUIRED */
+	png_write_info(png_ptr, info_ptr);
+
+	/* Once we write out the header, the compression type on the text
+	 * chunks gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
+	 * PNG_TEXT_COMPRESSION_zTXt_WR, so it doesn't get written out again
+	 * at the end.
+	 */
+
+	/* set up the transformations you want.  Note that these are
+	 * all optional.  Only call them if you want them.
+	 */
+
+	/* --- CUT --- */
+
+	/* The easiest way to write the image (you may have a different memory
+	 * layout, however, so choose what fits your needs best).  You need to
+	 * use the first method if you aren't handling interlacing yourself.
+	 */
+
+	r = 0;
+	while (r < static_cast< png_uint_32 > (height) ) {
+		png_bytep row_pointers[64];
+		int h, n;
+
+		h = MIN (height - r, 64);
+		n = get_rows ((const unsigned char **) row_pointers, r, h, data);
+		if (!n) break;
+		png_write_rows (png_ptr, row_pointers, n);
+		r += n;
+	}
+
+	/* You can write optional chunks like tEXt, zTXt, and tIME at the end
+	 * as well.
+	 */
+
+	/* It is REQUIRED to call this to finish writing the rest of the file */
+	png_write_end(png_ptr, info_ptr);
+
+	/* if you allocated any text comments, free them here */
+
+	/* clean up after the write, and free any memory allocated */
+	png_destroy_write_struct(&png_ptr, &info_ptr);
+
+	/* close the file */
+	fclose(fp);
+
+	/* that's it */
+	return TRUE;
+}
+