將png轉換為bmp格式
阿新 • • 發佈:2019-01-05
<?php $im = imagecreatefrompng("ok.png"); imagebmp($im,'ok.bmp',24); //imagedestroy($im); /** * 建立bmp格式圖片 * * @author: legend([email protected]) * @link: http://www.ugia.cn/?p=96 * @description: create Bitmap-File with GD library * @version: 0.1 * * @param resource $im 影象資源 * @param string $filename 如果要另存為檔案,請指定檔名,為空則直接在瀏覽器輸出 * @param integer $bit 影象質量(1、4、8、16、24、32位) * @param integer $compression 壓縮方式,0為不壓縮,1使用RLE8壓縮演算法進行壓縮 * * @return integer */ function imagebmp(&$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, $bit); // 調整調色盤 imagetruecolortopalette($im, true, $bits); $width = imagesx($im); $height = imagesy($im); $colors_num = imagecolorstotal($im); $rgb_quad = ''; if ($bit <= 8) { // 顏色索引 //$rgb_quad = ''; for ($i = 0; $i < $colors_num; $i ++) { $colors = imagecolorsforindex($im, $i); $rgb_quad .= chr($colors['blue']) . chr($colors['green']) . chr($colors['red']) . "\0"; } // 點陣圖資料 $bmp_data = ''; // 非壓縮 if ($compression == 0 || $bit < 8) { if (!in_array($bit, array(1, 4, 8))) { $bit = 8; } $compression = 0; // 每行位元組數必須為4的倍數,補齊。 $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 .= $extra; } } // RLE8 壓縮 else if ($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 { // 每行位元組數必須為4的倍數,補齊。 $extra = ''; $padding = 4 - ($width * ($bit / 8)) % 4; if ($padding % 4 != 0) { $extra = str_repeat("\0", $padding); } // 點陣圖資料 $bmp_data = ''; for ($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; } // 點陣圖檔案頭 $file_header = "BM" . pack("V3", 54 + $size_quad + $size_data, 0, 54 + $size_quad); // 點陣圖資訊頭 $info_header = pack("V3v2V*", 0x28, $width, $height, 1, $bit, $compression, $size_data, 0, 0, $colors_num, 0); // 寫入檔案 if ($filename != '') { $fp = fopen($filename, "wb"); fwrite($fp, $file_header); fwrite($fp, $info_header); fwrite($fp, $rgb_quad); fwrite($fp, $bmp_data); fclose($fp); return 1; } // 瀏覽器輸出 header("Content-Type: image/bmp"); echo $file_header . $info_header; echo $rgb_quad; echo $bmp_data; return 1; }