/** - * 创建bmp格式图片
- *
- * @author: legend
- * @description: create Bitmap-File with GD library
- * @version: 0.1
- *
- * @param resource $im 图像资源
- * @param string $filename 如果要另存为文件，请指定文件名，为空则直接在浏览器输出
- * @param integer $bit 图像质量(1、4、8、16、24、32位)
- * @param integer $compression 压缩方式，0为不压缩，1使用RLE8压缩算法进行压缩
- *
- * @return integer
- */
- function imagebmp(&$im, $filename = ”, $bit = 8, $compression = 0)
- {
- if (!in_array($bit, array(1, 4, 8, 16, 24, 32)))
- {
- $bit = 8;
- }
- else if ($bit == 32) // todo:32 bit
- {
- $bit = 24;
- }
$bits = pow(2, $bit); // 调整调色板 - imagetruecolortopalette($im, true, $bits);
- $width = imagesx($im);
- $height = imagesy($im);
- $colors_num = imagecolorstotal($im);
if ($bit <= 8) - {
- // 颜色索引
- $rgb_quad = ”;
- for ($i = 0; $i < $colors_num; $i ++)
- {
- $colors = imagecolorsforindex($im, $i);
- $rgb_quad .= chr($colors['blue']) . chr($colors['green']) . chr($colors['red']) . “\0″;
- }
// 位图数据 - $bmp_data = ”;
// 非压缩 - if ($compression == 0 || $bit < 8)
- {
- if (!in_array($bit, array(1, 4, 8)))
- {
- $bit = 8;
- }
$compression = 0; // 每行字节数必须为4的倍数，补齐。 - $extra = ”;
- $padding = 4 – ceil($width / (8 / $bit)) % 4;
- if ($padding % 4 != 0)
- {
- $extra = str_repeat(“\0″, $padding);
- }
for ($j = $height – 1; $j >= 0; $j –) - {
- $i = 0;
- while ($i < $width)
- {
- $bin = 0;
- $limit = $width – $i < 8 / $bit ? (8 / $bit - $width + $i) * $bit : 0;
for ($k = 8 – $bit; $k >= $limit; $k -= $bit) - {
- $index = imagecolorat($im, $i, $j);
- $bin |= $index << $k;
- $i ++;
- }
$bmp_data .= chr($bin); - }
$bmp_data .= $extra; - }
- }
- // RLE8 压缩
- else if ($compression == 1 && $bit == 8)
- {
- for ($j = $height – 1; $j >= 0; $j –)
- {
- $last_index = “\0″;
- $same_num = 0;
- for ($i = 0; $i <= $width; $i ++)
- {
- $index = imagecolorat($im, $i, $j);
- if ($index !== $last_index || $same_num > 255)
- {
- if ($same_num != 0)
- {
- $bmp_data .= chr($same_num) . chr($last_index);
- }
$last_index = $index; - $same_num = 1;
- }
- else
- {
- $same_num ++;
- }
- }
$bmp_data .= “\0\0″; - }
$bmp_data .= “\0\1″; - }
$size_quad = strlen($rgb_quad); - $size_data = strlen($bmp_data);
- }
- else
- {
- // 每行字节数必须为4的倍数，补齐。
- $extra = ”;
- $padding = 4 – ($width * ($bit / 8)) % 4;
- if ($padding % 4 != 0)
- {
- $extra = str_repeat(“\0″, $padding);
- }
// 位图数据 - $bmp_data = ”;
for ($j = $height – 1; $j >= 0; $j –) - {
- for ($i = 0; $i < $width; $i ++)
- {
- $index = imagecolorat($im, $i, $j);
- $colors = imagecolorsforindex($im, $index);
if ($bit == 16) - {
- $bin = 0 << $bit;
$bin |= ($colors['red'] >> 3) << 10; - $bin |= ($colors['green'] >> 3) << 5;
- $bin |= $colors['blue'] >> 3;
$bmp_data .= pack(“v”, $bin); - }
- else
- {
- $bmp_data .= pack(“c*”, $colors['blue'], $colors['green'], $colors['red']);
- }
// todo: 32bit; - }
$bmp_data .= $extra; - }
$size_quad = 0; - $size_data = strlen($bmp_data);
- $colors_num = 0;
- }
// 位图文件头 - $file_header = “BM” . pack(“V3″, 54 + $size_quad + $size_data, 0, 54 + $size_quad);
// 位图信息头 - $info_header = pack(“V3v2V*”, 0×28, $width, $height, 1, $bit, $compression, $size_data, 0, 0, $colors_num, 0);
// 写入文件 - if ($filename != ”)
- {
- $fp = fopen(“test.bmp”, “wb”);
fwrite($fp, $file_header); - fwrite($fp, $info_header);
- fwrite($fp, $rgb_quad);
- fwrite($fp, $bmp_data);
- fclose($fp);
return 1; - }
// 浏览器输出 - header(“Content-Type: image/bmp”);
- echo $file_header . $info_header;
- echo $rgb_quad;
- echo $bmp_data;
return 1; - }
- ?>
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