php对bmp图片的处理

由文件或 URL 创建一个新图象 ImageCreateFromBMP

function ImageCreateFromBMP($filename)
    {
        //php7.2支持
        if(function_exists("imagecreatefrombmp")){
            return imagecreatefrombmp($filename);
        }
        //Ouverture du fichier en mode binaire
        if (! $f1 = fopen($filename,"rb")) return FALSE;

        //1 : Chargement des ent�tes FICHIER
        $FILE = unpack("vfile_type/Vfile_size/Vreserved/Vbitmap_offset", fread($f1,14));

        if ($FILE['file_type'] != 19778) return FALSE;

        //2 : Chargement des ent�tes BMP
        $BMP = unpack('Vheader_size/Vwidth/Vheight/vplanes/vbits_per_pixel'.
            '/Vcompression/Vsize_bitmap/Vhoriz_resolution'.
            '/Vvert_resolution/Vcolors_used/Vcolors_important', fread($f1,40));
        $BMP['colors'] = pow(2,$BMP['bits_per_pixel']);
        if ($BMP['size_bitmap'] == 0) $BMP['size_bitmap'] = $FILE['file_size'] - $FILE['bitmap_offset'];
        $BMP['bytes_per_pixel'] = $BMP['bits_per_pixel']/8;
        $BMP['bytes_per_pixel2'] = ceil($BMP['bytes_per_pixel']);
        $BMP['decal'] = ($BMP['width']*$BMP['bytes_per_pixel']/4);
        $BMP['decal'] -= floor($BMP['width']*$BMP['bytes_per_pixel']/4);
        $BMP['decal'] = 4-(4*$BMP['decal']);
        if ($BMP['decal'] == 4) $BMP['decal'] = 0;

        //3 : Chargement des couleurs de la palette
        $PALETTE = array();
        if ($BMP['colors'] < 16777216)
        {
            $PALETTE = unpack('V'.$BMP['colors'], fread($f1,$BMP['colors']*4));
        }

        //4 : Creation de l'image
        $IMG = fread($f1,$BMP['size_bitmap']);
        $VIDE = chr(0);

        $res = imagecreatetruecolor($BMP['width'],$BMP['height']);
        $P = 0;
        $Y = $BMP['height']-1;
        while ($Y >= 0)
        {
            $X=0;
            while ($X < $BMP['width'])
            {
                if ($BMP['bits_per_pixel'] == 24)
                    $COLOR = unpack("V",substr($IMG,$P,3).$VIDE);
                elseif ($BMP['bits_per_pixel'] == 16)
                {
                    $COLOR = unpack("n",substr($IMG,$P,2));
                    $COLOR[1] = $PALETTE[$COLOR[1]+1];
                }
                elseif ($BMP['bits_per_pixel'] == 8)
                {
                    $COLOR = unpack("n",$VIDE.substr($IMG,$P,1));
                    $COLOR[1] = $PALETTE[$COLOR[1]+1];
                }
                elseif ($BMP['bits_per_pixel'] == 4)
                {
                    $COLOR = unpack("n",$VIDE.substr($IMG,floor($P),1));
                    if (($P*2)%2 == 0) $COLOR[1] = ($COLOR[1] >> 4) ; else $COLOR[1] = ($COLOR[1] & 0x0F);
                    $COLOR[1] = $PALETTE[$COLOR[1]+1];
                }
                elseif ($BMP['bits_per_pixel'] == 1)
                {
                    $COLOR = unpack("n",$VIDE.substr($IMG,floor($P),1));
                    if     (($P*8)%8 == 0) $COLOR[1] =  $COLOR[1]        >>7;
                    elseif (($P*8)%8 == 1) $COLOR[1] = ($COLOR[1] & 0x40)>>6;
                    elseif (($P*8)%8 == 2) $COLOR[1] = ($COLOR[1] & 0x20)>>5;
                    elseif (($P*8)%8 == 3) $COLOR[1] = ($COLOR[1] & 0x10)>>4;
                    elseif (($P*8)%8 == 4) $COLOR[1] = ($COLOR[1] & 0x8)>>3;
                    elseif (($P*8)%8 == 5) $COLOR[1] = ($COLOR[1] & 0x4)>>2;
                    elseif (($P*8)%8 == 6) $COLOR[1] = ($COLOR[1] & 0x2)>>1;
                    elseif (($P*8)%8 == 7) $COLOR[1] = ($COLOR[1] & 0x1);
                    $COLOR[1] = $PALETTE[$COLOR[1]+1];
                }
                else
                    return FALSE;
                imagesetpixel($res,$X,$Y,$COLOR[1]);
                $X++;
                $P += $BMP['bytes_per_pixel'];
            }
            $Y--;
            $P+=$BMP['decal'];
        }

        //Fermeture du fichier
        fclose($f1);

        return $res;
    }

生成或创建bmp图像 imagebmp

/**
 * 创建bmp格式图片
 *
 * [@author](https://my.oschina.net/arthor): legend(legendsky@hotmail.com)
 * [@link](https://my.oschina.net/u/393): http://www.ugia.cn/?p=96
 * @description: create Bitmap-File with GD library
 * [@version](https://my.oschina.net/u/931210): 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*", 0x28, $width, $height, 1, $bit, $compression, $size_data, 0, 0, $colors_num, 0);
    // 写入文件
    if ($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;
    }
    // 浏览器输出
    header("Content-Type: image/bmp");
    echo $file_header . $info_header;
    echo $rgb_quad;
    echo $bmp_data;
    return 1;
}

以上方法适用于php7.2以下版本 php7.2及以上版本可直接使用php内置函数

转载于:https://my.oschina.net/fage1151/blog/1831028

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