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Port "Transparent support for writing 1bpp and 4bpp BMPs" #17264

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82 changes: 63 additions & 19 deletions ext/gd/libgd/gd_bmp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -25,8 +25,8 @@
#include "gdhelpers.h"
#include "bmp.h"

static int compress_row(unsigned char *uncompressed_row, int length);
static int build_rle_packet(unsigned char *row, int packet_type, int length, unsigned char *data);
static int compress_row(unsigned char *uncompressed_row, int length, int ppbyte, int nibble);
static int build_rle_packet(unsigned char *row, int packet_type, int length, unsigned char *data, int ppbyte, int nibble);

static int bmp_read_header(gdIOCtxPtr infile, bmp_hdr_t *hdr);
static int bmp_read_info(gdIOCtxPtr infile, bmp_info_t *info);
Expand Down Expand Up @@ -90,6 +90,7 @@ void gdImageBmp(gdImagePtr im, FILE *outFile, int compression)
*/
void gdImageBmpCtx(gdImagePtr im, gdIOCtxPtr out, int compression)
{
int bpp, ppbyte, compression_method;
int bitmap_size = 0, info_size, total_size, padding;
int i, row, xpos, pixel;
int error = 0;
Expand All @@ -116,7 +117,17 @@ void gdImageBmpCtx(gdImagePtr im, gdIOCtxPtr out, int compression)
}
}

bitmap_size = ((im->sx * (im->trueColor ? 24 : 8)) / 8) * im->sy;
if (im->trueColor) {
bpp = 24;
} else if (im->colorsTotal <= 2 && !compression) {
bpp = 1;
} else if (im->colorsTotal <= 16) {
bpp = 4;
} else {
bpp = 8;
}
ppbyte = 8 / bpp; /* for palette images */
bitmap_size = ((im->sx * bpp + 7) / 8) * im->sy;

/* 40 byte Windows v3 header */
info_size = BMP_WINDOWS_V3;
Expand All @@ -132,6 +143,8 @@ void gdImageBmpCtx(gdImagePtr im, gdIOCtxPtr out, int compression)
/* bitmap header + info header + data */
total_size = 14 + info_size + bitmap_size;

compression_method = (compression ? (bpp >= 8 ? BMP_BI_RLE8 : BMP_BI_RLE4) : BMP_BI_RGB);

/* write bmp header info */
gdPutBuf("BM", 2, out);
gdBMPPutInt(out, total_size);
Expand All @@ -144,16 +157,20 @@ void gdImageBmpCtx(gdImagePtr im, gdIOCtxPtr out, int compression)
gdBMPPutInt(out, im->sx); /* width */
gdBMPPutInt(out, im->sy); /* height */
gdBMPPutWord(out, 1); /* colour planes */
gdBMPPutWord(out, (im->trueColor ? 24 : 8)); /* bit count */
gdBMPPutInt(out, (compression ? BMP_BI_RLE8 : BMP_BI_RGB)); /* compression */
gdBMPPutWord(out, bpp); /* bit count */
gdBMPPutInt(out, compression_method); /* compression */
gdBMPPutInt(out, bitmap_size); /* image size */
gdBMPPutInt(out, 0); /* H resolution */
gdBMPPutInt(out, 0); /* V ressolution */
gdBMPPutInt(out, im->colorsTotal); /* colours used */
gdBMPPutInt(out, 0); /* important colours */

/* The line must be divisible by 4, else it's padded with NULLs */
padding = ((int)(im->trueColor ? 3 : 1) * im->sx) % 4;
if (bpp < 8) {
padding = (im->sx + ppbyte - 1) / ppbyte % 4;
} else {
padding = ((int)(im->trueColor ? 3 : 1) * im->sx) % 4;
}
if (padding) {
padding = 4 - padding;
}
Expand All @@ -177,13 +194,37 @@ void gdImageBmpCtx(gdImagePtr im, gdIOCtxPtr out, int compression)
}

for (row = (im->sy - 1); row >= 0; row--) {
int byte = 0;
if (compression) {
memset (uncompressed_row, 0, gdImageSX(im));
}

for (xpos = 0; xpos < im->sx; xpos++) {
if (compression) {
if (compression && bpp < 8) {
byte = (byte << bpp) + gdImageGetPixel(im, xpos, row);
if (xpos % 2 == 1) {
*uncompressed_row++ = (unsigned char) byte;
byte = 0;
} else if (xpos + 1 == im->sx) {
/* imcomplete byte at end of row */
byte <<= bpp;
*uncompressed_row++ = (unsigned char) byte;
byte = 0;
}
} else if (compression) {
*uncompressed_row++ = (unsigned char)gdImageGetPixel(im, xpos, row);
} else if (bpp < 8) {
int next_chunk_in_byte = (xpos + 1) % ppbyte;
byte = (byte << bpp) + gdImageGetPixel(im, xpos, row);
if (next_chunk_in_byte == 0) {
Putchar(byte, out);
byte = 0;
} else if (xpos + 1 == im->sx) {
/* imcomplete byte at end of row */
byte <<= bpp * (ppbyte - next_chunk_in_byte);
Putchar(byte, out);
byte = 0;
}
} else {
Putchar(gdImageGetPixel(im, xpos, row), out);
}
Expand All @@ -196,8 +237,10 @@ void gdImageBmpCtx(gdImagePtr im, gdIOCtxPtr out, int compression)
}
} else {
int compressed_size = 0;
int length = (gdImageSX(im) + ppbyte - 1) / ppbyte;
int nibble = gdImageSX(im) % ppbyte;
uncompressed_row = uncompressed_row_start;
if ((compressed_size = compress_row(uncompressed_row, gdImageSX(im))) < 0) {
if ((compressed_size = compress_row(uncompressed_row, length, ppbyte, nibble)) < 0) {
error = 1;
break;
}
Expand Down Expand Up @@ -289,7 +332,7 @@ void gdImageBmpCtx(gdImagePtr im, gdIOCtxPtr out, int compression)
return;
}

static int compress_row(unsigned char *row, int length)
static int compress_row(unsigned char *row, int length, int ppbyte, int nibble)
{
int rle_type = 0;
int compressed_length = 0;
Expand Down Expand Up @@ -321,9 +364,9 @@ static int compress_row(unsigned char *row, int length)
}

if (rle_type == BMP_RLE_TYPE_RLE) {
if (compressed_run >= 128 || memcmp(uncompressed_rowp, uncompressed_rowp - 1, 1) != 0) {
if (compressed_run >= 127 || memcmp(uncompressed_rowp, uncompressed_rowp - 1, 1) != 0) {
/* more than what we can store in a single run or run is over due to non match, force write */
rle_compression = build_rle_packet(row, rle_type, compressed_run, uncompressed_row);
rle_compression = build_rle_packet(row, rle_type, compressed_run, uncompressed_row, ppbyte, 0);
row += rle_compression;
compressed_length += rle_compression;
compressed_run = 0;
Expand All @@ -333,9 +376,9 @@ static int compress_row(unsigned char *row, int length)
uncompressed_rowp++;
}
} else {
if (compressed_run >= 128 || memcmp(uncompressed_rowp, uncompressed_rowp - 1, 1) == 0) {
if (compressed_run >= 127 || memcmp(uncompressed_rowp, uncompressed_rowp - 1, 1) == 0) {
/* more than what we can store in a single run or run is over due to match, force write */
rle_compression = build_rle_packet(row, rle_type, compressed_run, uncompressed_row);
rle_compression = build_rle_packet(row, rle_type, compressed_run, uncompressed_row, ppbyte, 0);
row += rle_compression;
compressed_length += rle_compression;
compressed_run = 0;
Expand All @@ -349,19 +392,20 @@ static int compress_row(unsigned char *row, int length)
}
}

/* the following condition is always true */
if (compressed_run) {
compressed_length += build_rle_packet(row, rle_type, compressed_run, uncompressed_row);
compressed_length += build_rle_packet(row, rle_type, compressed_run, uncompressed_row, ppbyte, nibble);
}

gdFree(uncompressed_start);

return compressed_length;
}

static int build_rle_packet(unsigned char *row, int packet_type, int length, unsigned char *data)
static int build_rle_packet(unsigned char *row, int packet_type, int length, unsigned char *data, int ppbyte, int nibble)
{
int compressed_size = 0;
if (length < 1 || length > 128) {
if (length < 1 || length > 127) {
return 0;
}

Expand All @@ -370,15 +414,15 @@ static int build_rle_packet(unsigned char *row, int packet_type, int length, uns
int i = 0;
for (i = 0; i < length; i++) {
compressed_size += 2;
memset(row, 1, 1);
memset(row, ppbyte * 1 - (i + 1 == length ? nibble : 0), 1);
row++;

memcpy(row, data++, 1);
row++;
}
} else if (packet_type == BMP_RLE_TYPE_RLE) {
compressed_size = 2;
memset(row, length, 1);
memset(row, ppbyte * length - nibble, 1);
row++;

memcpy(row, data, 1);
Expand All @@ -388,7 +432,7 @@ static int build_rle_packet(unsigned char *row, int packet_type, int length, uns
memset(row, BMP_RLE_COMMAND, 1);
row++;

memset(row, length, 1);
memset(row, ppbyte * length - nibble, 1);
row++;

memcpy(row, data, length);
Expand Down
99 changes: 99 additions & 0 deletions ext/gd/tests/bmp_low_depth.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,99 @@
--TEST--
Bitmaps with bpp < 8
--EXTENSIONS--
gd
--FILE--
<?php
require __DIR__ . "/func.inc";

$filename = __DIR__ . "/bmp_low_depth.bmp";

// 2 color image
$im1 = imagecreate(99, 99); // odd pixels per row!
imagecolorallocate($im1, 0, 0, 0); // background
$fg = imagecolorallocate($im1, 255, 255, 255);
imagerectangle($im1, 0, 0, 98, 98, $fg); // border to verify edge case
imageellipse($im1, 49, 49, 75, 75, $fg);

echo "1bpp uncompressed\n";
imagebmp($im1, $filename, false);
$data = file_get_contents($filename, false, null, 0x1c, 6);
var_dump(unpack("vbpp/Vcomp", $data));
$im2 = imagecreatefrombmp($filename);
test_image_equals_image($im1, $im2);

echo "\n1bpp compressed\n";
imagebmp($im1, $filename, true);
$data = file_get_contents($filename, false, null, 0x1c, 6);
var_dump(unpack("vbpp/Vcomp", $data));
$im2 = imagecreatefrombmp($filename);
test_image_equals_image($im1, $im2);

// 5 color image
$r = imagecolorallocate($im1, 255, 0, 0);
$g = imagecolorallocate($im1, 0, 255, 0);
$b = imagecolorallocate($im1, 0, 0, 255);
imageellipse($im1, 17, 17, 28, 28, $r);
imageellipse($im1, 49, 17, 28, 28, $r);
imageellipse($im1, 81, 17, 28, 28, $r);
imageellipse($im1, 17, 49, 28, 28, $g);
imageellipse($im1, 49, 49, 28, 28, $g);
imageellipse($im1, 81, 49, 28, 28, $g);
imageellipse($im1, 17, 81, 28, 28, $b);
imageellipse($im1, 49, 81, 28, 28, $b);
imageellipse($im1, 81, 81, 28, 28, $b);

echo "\n4bpp uncompressed\n";
imagebmp($im1, $filename, false);
$data = file_get_contents($filename, false, null, 0x1c, 6);
var_dump(unpack("vbpp/Vcomp", $data));
$im2 = imagecreatefrombmp($filename);
test_image_equals_image($im1, $im2);

echo "\n4bpp compressed\n";
imagebmp($im1, $filename, true);
$data = file_get_contents($filename, false, null, 0x1c, 6);
var_dump(unpack("vbpp/Vcomp", $data));
$im2 = imagecreatefrombmp($filename);
test_image_equals_image($im1, $im2);
?>
--EXPECT--
1bpp uncompressed
array(2) {
["bpp"]=>
int(1)
["comp"]=>
int(0)
}
The images are equal.

1bpp compressed
array(2) {
["bpp"]=>
int(4)
["comp"]=>
int(2)
}
The images are equal.

4bpp uncompressed
array(2) {
["bpp"]=>
int(4)
["comp"]=>
int(0)
}
The images are equal.

4bpp compressed
array(2) {
["bpp"]=>
int(4)
["comp"]=>
int(2)
}
The images are equal.
--CLEAN--
<?php
@unlink(__DIR__ . "/bmp_low_depth.bmp");
?>
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