--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/source/fitz/load-png.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,704 @@
+// Copyright (C) 2004-2021 Artifex Software, Inc.
+//
+// This file is part of MuPDF.
+//
+// MuPDF is free software: you can redistribute it and/or modify it under the
+// terms of the GNU Affero General Public License as published by the Free
+// Software Foundation, either version 3 of the License, or (at your option)
+// any later version.
+//
+// MuPDF 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 Affero General Public License for more
+// details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with MuPDF. If not, see <https://www.gnu.org/licenses/agpl-3.0.en.html>
+//
+// Alternative licensing terms are available from the licensor.
+// For commercial licensing, see <https://www.artifex.com/> or contact
+// Artifex Software, Inc., 39 Mesa Street, Suite 108A, San Francisco,
+// CA 94129, USA, for further information.
+
+#include "mupdf/fitz.h"
+
+#include "pixmap-imp.h"
+#include "z-imp.h"
+
+#include <limits.h>
+#include <string.h>
+
+struct info
+{
+	unsigned int width, height, depth, n;
+	enum fz_colorspace_type type;
+	int interlace, indexed;
+	size_t size;
+	unsigned char *samples;
+	unsigned char palette[256*4];
+	int transparency;
+	int trns[3];
+	int xres, yres;
+	fz_colorspace *cs;
+};
+
+static inline unsigned int getuint(const unsigned char *p)
+{
+	return p[0] << 24 | p[1] << 16 | p[2] << 8 | p[3];
+}
+
+static inline int getcomp(const unsigned char *line, int x, int bpc)
+{
+	switch (bpc)
+	{
+	case 1: return (line[x >> 3] >> ( 7 - (x & 7) ) ) & 1;
+	case 2: return (line[x >> 2] >> ( ( 3 - (x & 3) ) << 1 ) ) & 3;
+	case 4: return (line[x >> 1] >> ( ( 1 - (x & 1) ) << 2 ) ) & 15;
+	case 8: return line[x];
+	case 16: return line[x << 1] << 8 | line[(x << 1) + 1];
+	}
+	return 0;
+}
+
+static inline void putcomp(unsigned char *line, int x, int bpc, int value)
+{
+	int maxval = (1 << bpc) - 1;
+
+	switch (bpc)
+	{
+	case 1: line[x >> 3] &= ~(maxval << (7 - (x & 7))); break;
+	case 2: line[x >> 2] &= ~(maxval << ((3 - (x & 3)) << 1)); break;
+	case 4: line[x >> 1] &= ~(maxval << ((1 - (x & 1)) << 2)); break;
+	}
+
+	switch (bpc)
+	{
+	case 1: line[x >> 3] |= value << (7 - (x & 7)); break;
+	case 2: line[x >> 2] |= value << ((3 - (x & 3)) << 1); break;
+	case 4: line[x >> 1] |= value << ((1 - (x & 1)) << 2); break;
+	case 8: line[x] = value; break;
+	case 16: line[x << 1] = value >> 8; line[(x << 1) + 1] = value & 0xFF; break;
+	}
+}
+
+static const unsigned char png_signature[8] =
+{
+	137, 80, 78, 71, 13, 10, 26, 10
+};
+
+static inline int paeth(int a, int b, int c)
+{
+	/* The definitions of ac and bc are correct, not a typo. */
+	int ac = b - c, bc = a - c, abcc = ac + bc;
+	int pa = (ac < 0 ? -ac : ac);
+	int pb = (bc < 0 ? -bc : bc);
+	int pc = (abcc < 0 ? -abcc : abcc);
+	return pa <= pb && pa <= pc ? a : pb <= pc ? b : c;
+}
+
+static void
+png_predict(unsigned char *samples, unsigned int width, unsigned int height, unsigned int n, unsigned int depth)
+{
+	unsigned int stride = (width * n * depth + 7) / 8;
+	unsigned int bpp = (n * depth + 7) / 8;
+	unsigned int i, row;
+
+	for (row = 0; row < height; row ++)
+	{
+		unsigned char *src = samples + (unsigned int)((stride + 1) * row);
+		unsigned char *dst = samples + (unsigned int)(stride * row);
+
+		unsigned char *a = dst;
+		unsigned char *b = dst - stride;
+		unsigned char *c = dst - stride;
+
+		switch (*src++)
+		{
+		default:
+		case 0: /* None */
+			for (i = 0; i < stride; i++)
+				*dst++ = *src++;
+			break;
+
+		case 1: /* Sub */
+			for (i = 0; i < bpp; i++)
+				*dst++ = *src++;
+			for (i = bpp; i < stride; i++)
+				*dst++ = *src++ + *a++;
+			break;
+
+		case 2: /* Up */
+			if (row == 0)
+				for (i = 0; i < stride; i++)
+					*dst++ = *src++;
+			else
+				for (i = 0; i < stride; i++)
+					*dst++ = *src++ + *b++;
+			break;
+
+		case 3: /* Average */
+			if (row == 0)
+			{
+				for (i = 0; i < bpp; i++)
+					*dst++ = *src++;
+				for (i = bpp; i < stride; i++)
+					*dst++ = *src++ + (*a++ >> 1);
+			}
+			else
+			{
+				for (i = 0; i < bpp; i++)
+					*dst++ = *src++ + (*b++ >> 1);
+				for (i = bpp; i < stride; i++)
+					*dst++ = *src++ + ((*b++ + *a++) >> 1);
+			}
+			break;
+
+		case 4: /* Paeth */
+			if (row == 0)
+			{
+				for (i = 0; i < bpp; i++)
+					*dst++ = *src++ + paeth(0, 0, 0);
+				for (i = bpp; i < stride; i++)
+					*dst++ = *src++ + paeth(*a++, 0, 0);
+			}
+			else
+			{
+				for (i = 0; i < bpp; i++)
+					*dst++ = *src++ + paeth(0, *b++, 0);
+				for (i = bpp; i < stride; i++)
+					*dst++ = *src++ + paeth(*a++, *b++, *c++);
+			}
+			break;
+		}
+	}
+}
+
+static const unsigned int adam7_ix[7] = { 0, 4, 0, 2, 0, 1, 0 };
+static const unsigned int adam7_dx[7] = { 8, 8, 4, 4, 2, 2, 1 };
+static const unsigned int adam7_iy[7] = { 0, 0, 4, 0, 2, 0, 1 };
+static const unsigned int adam7_dy[7] = { 8, 8, 8, 4, 4, 2, 2 };
+
+static void
+png_deinterlace_passes(fz_context *ctx, struct info *info, unsigned int *w, unsigned int *h, unsigned int *ofs)
+{
+	int p, bpp = info->depth * info->n;
+	ofs[0] = 0;
+	for (p = 0; p < 7; p++)
+	{
+		w[p] = (info->width + adam7_dx[p] - adam7_ix[p] - 1) / adam7_dx[p];
+		h[p] = (info->height + adam7_dy[p] - adam7_iy[p] - 1) / adam7_dy[p];
+		if (w[p] == 0) h[p] = 0;
+		if (h[p] == 0) w[p] = 0;
+		if (w[p] && h[p])
+			ofs[p + 1] = ofs[p] + h[p] * (1 + (w[p] * bpp + 7) / 8);
+		else
+			ofs[p + 1] = ofs[p];
+	}
+}
+
+static void
+png_deinterlace(fz_context *ctx, struct info *info, unsigned int *passw, unsigned int *passh, unsigned int *passofs)
+{
+	unsigned int n = info->n;
+	unsigned int depth = info->depth;
+	size_t stride = ((size_t)info->width * n * depth + 7) / 8;
+	unsigned char *output;
+	unsigned int p, x, y, k;
+
+	if (info->height > UINT_MAX / stride)
+		fz_throw(ctx, FZ_ERROR_LIMIT, "image too large");
+	output = Memento_label(fz_malloc(ctx, info->height * stride), "png_deinterlace");
+
+	for (p = 0; p < 7; p++)
+	{
+		unsigned char *sp = info->samples + (passofs[p]);
+		unsigned int w = passw[p];
+		unsigned int h = passh[p];
+
+		png_predict(sp, w, h, n, depth);
+		for (y = 0; y < h; y++)
+		{
+			for (x = 0; x < w; x++)
+			{
+				int outx = x * adam7_dx[p] + adam7_ix[p];
+				int outy = y * adam7_dy[p] + adam7_iy[p];
+				unsigned char *dp = output + outy * stride;
+				for (k = 0; k < n; k++)
+				{
+					int v = getcomp(sp, x * n + k, depth);
+					putcomp(dp, outx * n + k, depth, v);
+				}
+			}
+			sp += (w * depth * n + 7) / 8;
+		}
+	}
+
+	fz_free(ctx, info->samples);
+	info->samples = output;
+}
+
+static void
+png_read_ihdr(fz_context *ctx, struct info *info, const unsigned char *p, unsigned int size)
+{
+	int color, compression, filter;
+
+	if (size != 13)
+		fz_throw(ctx, FZ_ERROR_FORMAT, "IHDR chunk is the wrong size");
+
+	info->width = getuint(p + 0);
+	info->height = getuint(p + 4);
+	info->depth = p[8];
+
+	color = p[9];
+	compression = p[10];
+	filter = p[11];
+	info->interlace = p[12];
+
+	if (info->width <= 0)
+		fz_throw(ctx, FZ_ERROR_FORMAT, "image width must be > 0");
+	if (info->height <= 0)
+		fz_throw(ctx, FZ_ERROR_FORMAT, "image height must be > 0");
+
+	if (info->depth != 1 && info->depth != 2 && info->depth != 4 &&
+			info->depth != 8 && info->depth != 16)
+		fz_throw(ctx, FZ_ERROR_FORMAT, "image bit depth must be one of 1, 2, 4, 8, 16");
+	if (color == 2 && info->depth < 8)
+		fz_throw(ctx, FZ_ERROR_FORMAT, "illegal bit depth for truecolor");
+	if (color == 3 && info->depth > 8)
+		fz_throw(ctx, FZ_ERROR_FORMAT, "illegal bit depth for indexed");
+	if (color == 4 && info->depth < 8)
+		fz_throw(ctx, FZ_ERROR_FORMAT, "illegal bit depth for grayscale with alpha");
+	if (color == 6 && info->depth < 8)
+		fz_throw(ctx, FZ_ERROR_FORMAT, "illegal bit depth for truecolor with alpha");
+
+	info->indexed = 0;
+	if (color == 0) /* gray */
+		info->n = 1, info->type = FZ_COLORSPACE_GRAY;
+	else if (color == 2) /* rgb */
+		info->n = 3, info->type = FZ_COLORSPACE_RGB;
+	else if (color == 4) /* gray alpha */
+		info->n = 2, info->type = FZ_COLORSPACE_GRAY;
+	else if (color == 6) /* rgb alpha */
+		info->n = 4, info->type = FZ_COLORSPACE_RGB;
+	else if (color == 3) /* indexed */
+	{
+		info->type = FZ_COLORSPACE_RGB; /* after colorspace expansion it will be */
+		info->indexed = 1;
+		info->n = 1;
+	}
+	else
+		fz_throw(ctx, FZ_ERROR_FORMAT, "unknown color type");
+
+	if (compression != 0)
+		fz_throw(ctx, FZ_ERROR_FORMAT, "unknown compression method");
+	if (filter != 0)
+		fz_throw(ctx, FZ_ERROR_FORMAT, "unknown filter method");
+	if (info->interlace != 0 && info->interlace != 1)
+		fz_throw(ctx, FZ_ERROR_FORMAT, "interlace method not supported");
+	if (info->height > UINT_MAX / info->width / info->n / (info->depth / 8 + 1))
+		fz_throw(ctx, FZ_ERROR_LIMIT, "image dimensions might overflow");
+}
+
+static void
+png_read_plte(fz_context *ctx, struct info *info, const unsigned char *p, unsigned int size)
+{
+	int n = size / 3;
+	int i;
+
+	if (n > 256)
+	{
+		fz_warn(ctx, "too many samples in palette");
+		n = 256;
+	}
+
+	for (i = 0; i < n; i++)
+	{
+		info->palette[i * 4] = p[i * 3];
+		info->palette[i * 4 + 1] = p[i * 3 + 1];
+		info->palette[i * 4 + 2] = p[i * 3 + 2];
+	}
+
+	/* Fill in any missing palette entries */
+	for (; i < 256; i++)
+	{
+		info->palette[i * 4] = 0;
+		info->palette[i * 4 + 1] = 0;
+		info->palette[i * 4 + 2] = 0;
+	}
+}
+
+static void
+png_read_trns(fz_context *ctx, struct info *info, const unsigned char *p, unsigned int size)
+{
+	unsigned int i;
+
+	info->transparency = 1;
+
+	if (info->indexed)
+	{
+		if (size > 256)
+		{
+			fz_warn(ctx, "too many samples in transparency table");
+			size = 256;
+		}
+		for (i = 0; i < size; i++)
+			info->palette[i * 4 + 3] = p[i];
+		/* Fill in any missing entries */
+		for (; i < 256; i++)
+			info->palette[i * 4 + 3] = 255;
+	}
+	else
+	{
+		if (size != info->n * 2)
+			fz_throw(ctx, FZ_ERROR_FORMAT, "tRNS chunk is the wrong size");
+		for (i = 0; i < info->n; i++)
+			info->trns[i] = (p[i * 2] << 8 | p[i * 2 + 1]) & ((1 << info->depth) - 1);
+	}
+}
+
+static void
+png_read_icc(fz_context *ctx, struct info *info, const unsigned char *p, unsigned int size)
+{
+#if FZ_ENABLE_ICC
+	fz_stream *mstm = NULL, *zstm = NULL;
+	fz_colorspace *cs = NULL;
+	fz_buffer *buf = NULL;
+	size_t m = fz_mini(80, size);
+	size_t n = fz_strnlen((const char *)p, m);
+	if (n + 2 > m)
+	{
+		fz_warn(ctx, "invalid ICC profile name");
+		return;
+	}
+
+	fz_var(mstm);
+	fz_var(zstm);
+	fz_var(buf);
+
+	fz_try(ctx)
+	{
+		mstm = fz_open_memory(ctx, p + n + 2, size - n - 2);
+		zstm = fz_open_flated(ctx, mstm, 15);
+		buf = fz_read_all(ctx, zstm, 0);
+		cs = fz_new_icc_colorspace(ctx, info->type, 0, NULL, buf);
+		fz_drop_colorspace(ctx, info->cs);
+		info->cs = cs;
+	}
+	fz_always(ctx)
+	{
+		fz_drop_buffer(ctx, buf);
+		fz_drop_stream(ctx, zstm);
+		fz_drop_stream(ctx, mstm);
+	}
+	fz_catch(ctx)
+	{
+		fz_rethrow_if(ctx, FZ_ERROR_SYSTEM);
+		fz_report_error(ctx);
+		fz_warn(ctx, "ignoring embedded ICC profile in PNG");
+	}
+#endif
+}
+
+static void
+png_read_idat(fz_context *ctx, struct info *info, const unsigned char *p, unsigned int size, z_stream *stm)
+{
+	int code;
+
+	stm->next_in = (Bytef*)p;
+	stm->avail_in = size;
+
+	code = inflate(stm, Z_SYNC_FLUSH);
+	if (code != Z_OK && code != Z_STREAM_END)
+		fz_throw(ctx, FZ_ERROR_LIBRARY, "zlib error: %s", stm->msg);
+	if (stm->avail_in != 0)
+	{
+		if (stm->avail_out == 0)
+			fz_throw(ctx, FZ_ERROR_FORMAT, "ran out of output before input");
+		fz_throw(ctx, FZ_ERROR_FORMAT, "inflate did not consume buffer (%d remaining)", stm->avail_in);
+	}
+}
+
+static void
+png_read_phys(fz_context *ctx, struct info *info, const unsigned char *p, unsigned int size)
+{
+	if (size != 9)
+		fz_throw(ctx, FZ_ERROR_FORMAT, "pHYs chunk is the wrong size");
+	if (p[8] == 1)
+	{
+		info->xres = (getuint(p) * 254 + 5000) / 10000;
+		info->yres = (getuint(p + 4) * 254 + 5000) / 10000;
+	}
+}
+
+static void
+png_read_image(fz_context *ctx, struct info *info, const unsigned char *p, size_t total, int only_metadata)
+{
+	unsigned int passw[7], passh[7], passofs[8];
+	unsigned int code, size;
+	z_stream stm;
+
+	memset(info, 0, sizeof (struct info));
+	memset(info->palette, 255, sizeof(info->palette));
+	info->xres = 96;
+	info->yres = 96;
+
+	/* Read signature */
+
+	if (total < 8 + 12 || memcmp(p, png_signature, 8))
+		fz_throw(ctx, FZ_ERROR_FORMAT, "not a png image (wrong signature)");
+
+	p += 8;
+	total -= 8;
+
+	/* Read IHDR chunk (must come first) */
+
+	size = getuint(p);
+	if (size > total - 12)
+		fz_throw(ctx, FZ_ERROR_FORMAT, "premature end of data in png image");
+
+	if (!memcmp(p + 4, "IHDR", 4))
+		png_read_ihdr(ctx, info, p + 8, size);
+	else
+		fz_throw(ctx, FZ_ERROR_FORMAT, "png file must start with IHDR chunk");
+
+	p += size + 12;
+	total -= size + 12;
+
+	/* Prepare output buffer */
+	if (!only_metadata)
+	{
+		if (!info->interlace)
+		{
+			info->size = info->height * (1 + ((size_t) info->width * info->n * info->depth + 7) / 8);
+		}
+		else
+		{
+			png_deinterlace_passes(ctx, info, passw, passh, passofs);
+			info->size = passofs[7];
+		}
+
+		info->samples = Memento_label(fz_malloc(ctx, info->size), "png_samples");
+
+		stm.zalloc = fz_zlib_alloc;
+		stm.zfree = fz_zlib_free;
+		stm.opaque = ctx;
+
+		stm.next_out = info->samples;
+		stm.avail_out = (uInt)info->size;
+
+		code = inflateInit(&stm);
+		if (code != Z_OK)
+			fz_throw(ctx, FZ_ERROR_LIBRARY, "zlib error: %s", stm.msg);
+	}
+
+	fz_try(ctx)
+	{
+		/* Read remaining chunks until IEND */
+		while (total > 8)
+		{
+			size = getuint(p);
+
+			if (total < 12 || size > total - 12)
+				fz_throw(ctx, FZ_ERROR_FORMAT, "premature end of data in png image");
+
+			if (!memcmp(p + 4, "PLTE", 4) && !only_metadata)
+				png_read_plte(ctx, info, p + 8, size);
+			if (!memcmp(p + 4, "tRNS", 4) && !only_metadata)
+				png_read_trns(ctx, info, p + 8, size);
+			if (!memcmp(p + 4, "pHYs", 4))
+				png_read_phys(ctx, info, p + 8, size);
+			if (!memcmp(p + 4, "IDAT", 4) && !only_metadata)
+				png_read_idat(ctx, info, p + 8, size, &stm);
+			if (!memcmp(p + 4, "iCCP", 4))
+				png_read_icc(ctx, info, p + 8, size);
+			if (!memcmp(p + 4, "IEND", 4))
+				break;
+
+			p += size + 12;
+			total -= size + 12;
+		}
+		if (!only_metadata && stm.avail_out != 0)
+		{
+			memset(stm.next_out, 0xff, stm.avail_out);
+			fz_warn(ctx, "missing pixel data in png image; possibly truncated");
+		}
+		else if (total <= 8)
+			fz_warn(ctx, "missing IEND chunk in png image; possibly truncated");
+	}
+	fz_catch(ctx)
+	{
+		if (!only_metadata)
+		{
+			inflateEnd(&stm);
+			fz_free(ctx, info->samples);
+			info->samples = NULL;
+		}
+		fz_rethrow(ctx);
+	}
+
+	if (!only_metadata)
+	{
+		code = inflateEnd(&stm);
+		if (code != Z_OK)
+		{
+			fz_free(ctx, info->samples);
+			info->samples = NULL;
+			fz_throw(ctx, FZ_ERROR_LIBRARY, "zlib error: %s", stm.msg);
+		}
+
+		/* Apply prediction filter and deinterlacing */
+		fz_try(ctx)
+		{
+			if (!info->interlace)
+				png_predict(info->samples, info->width, info->height, info->n, info->depth);
+			else
+				png_deinterlace(ctx, info, passw, passh, passofs);
+		}
+		fz_catch(ctx)
+		{
+			fz_free(ctx, info->samples);
+			info->samples = NULL;
+			fz_rethrow(ctx);
+		}
+	}
+
+	if (info->cs && fz_colorspace_type(ctx, info->cs) != info->type)
+	{
+		fz_warn(ctx, "embedded ICC profile does not match PNG colorspace");
+		fz_drop_colorspace(ctx, info->cs);
+		info->cs = NULL;
+	}
+
+	if (info->cs == NULL)
+	{
+		if (info->n == 3 || info->n == 4 || info->indexed)
+			info->cs = fz_keep_colorspace(ctx, fz_device_rgb(ctx));
+		else
+			info->cs = fz_keep_colorspace(ctx, fz_device_gray(ctx));
+	}
+}
+
+static fz_pixmap *
+png_expand_palette(fz_context *ctx, struct info *info, fz_pixmap *src)
+{
+	fz_pixmap *dst = fz_new_pixmap(ctx, info->cs, src->w, src->h, NULL, info->transparency);
+	unsigned char *sp = src->samples;
+	unsigned char *dp = dst->samples;
+	unsigned int x, y;
+	size_t dstride = dst->stride - dst->w * (size_t)dst->n;
+	size_t sstride = src->stride - src->w * (size_t)src->n;
+
+	dst->xres = src->xres;
+	dst->yres = src->yres;
+
+	for (y = info->height; y > 0; y--)
+	{
+		for (x = info->width; x > 0; x--)
+		{
+			int v = *sp << 2;
+			*dp++ = info->palette[v];
+			*dp++ = info->palette[v + 1];
+			*dp++ = info->palette[v + 2];
+			if (info->transparency)
+				*dp++ = info->palette[v + 3];
+			++sp;
+		}
+		sp += sstride;
+		dp += dstride;
+	}
+
+	fz_drop_pixmap(ctx, src);
+	return dst;
+}
+
+static void
+png_mask_transparency(struct info *info, fz_pixmap *dst)
+{
+	unsigned int stride = (info->width * info->n * info->depth + 7) / 8;
+	unsigned int depth = info->depth;
+	unsigned int n = info->n;
+	unsigned int x, y, k, t;
+
+	for (y = 0; y < info->height; y++)
+	{
+		unsigned char *sp = info->samples + (unsigned int)(y * stride);
+		unsigned char *dp = dst->samples + (unsigned int)(y * dst->stride);
+		for (x = 0; x < info->width; x++)
+		{
+			t = 1;
+			for (k = 0; k < n; k++)
+				if (getcomp(sp, x * n + k, depth) != info->trns[k])
+					t = 0;
+			if (t)
+				dp[x * dst->n + dst->n - 1] = 0;
+		}
+	}
+}
+
+fz_pixmap *
+fz_load_png(fz_context *ctx, const unsigned char *p, size_t total)
+{
+	fz_pixmap *image = NULL;
+	struct info png;
+	size_t stride;
+	int alpha;
+
+	fz_var(image);
+
+	fz_try(ctx)
+	{
+		png_read_image(ctx, &png, p, total, 0);
+
+		stride = ((size_t) png.width * png.n * png.depth + 7) / 8;
+		alpha = (png.n == 2 || png.n == 4 || png.transparency);
+
+		if (png.indexed)
+		{
+			image = fz_new_pixmap(ctx, NULL, png.width, png.height, NULL, 1);
+			fz_unpack_tile(ctx, image, png.samples, png.n, png.depth, stride, 1);
+			image = png_expand_palette(ctx, &png, image);
+		}
+		else
+		{
+			image = fz_new_pixmap(ctx, png.cs, png.width, png.height, NULL, alpha);
+			fz_unpack_tile(ctx, image, png.samples, png.n, png.depth, stride, 0);
+			if (png.transparency)
+				png_mask_transparency(&png, image);
+		}
+		if (alpha)
+			fz_premultiply_pixmap(ctx, image);
+		fz_set_pixmap_resolution(ctx, image, png.xres, png.yres);
+	}
+	fz_always(ctx)
+	{
+		fz_drop_colorspace(ctx, png.cs);
+		fz_free(ctx, png.samples);
+	}
+	fz_catch(ctx)
+	{
+		fz_drop_pixmap(ctx, image);
+		fz_rethrow(ctx);
+	}
+
+	return image;
+}
+
+void
+fz_load_png_info(fz_context *ctx, const unsigned char *p, size_t total, int *wp, int *hp, int *xresp, int *yresp, fz_colorspace **cspacep)
+{
+	struct info png;
+
+	fz_try(ctx)
+		png_read_image(ctx, &png, p, total, 1);
+	fz_catch(ctx)
+	{
+		fz_drop_colorspace(ctx, png.cs);
+		fz_rethrow(ctx);
+	}
+
+	*cspacep = png.cs;
+	*wp = png.width;
+	*hp = png.height;
+	*xresp = png.xres;
+	*yresp = png.xres;
+}