spotweb/spotweb

<?php

class Services_Image_BmpConverter
{
    /*
     * Converts an image string to an JPEG file
     */
    public function convertBmpImageStringToJpeg($imageString, $dimensions)
    {
        /*
         * If this fil is currently an BMP, change it to an
         * JPG file
         */
        if ($dimensions['imagetype'] == 6) {
            /*
             * PHP image functions require an actual file,
             * so we create one
             */
            $srcFname = tempnam(sys_get_temp_dir(), 'SpotWeb_');
            $dstFname = tempnam(sys_get_temp_dir(), 'SpotWeb_');

            $fh = fopen($srcFname, 'w');
            fwrite($fh, $imageString);
            fclose($fh);

            /*
             * Convert the image from BMP to an JPEG. The function
             * we use needs both a source file and a destination file
             * so lets create those
             */

            if ($this->bmp2gd($srcFname, $dstFname)) {
                $tmpImg = imagecreatefromgd($dstFname);
            } else {
                $tmpImg = false;
            } // else

            /*
             * Remove the tempfiles
             */
            unlink($dstFname);
            unlink($srcFname);

            /*
             * If conversion somehow failed, don't bother anymore
             */
            if (!is_resource($tmpImg)) {
                return false;
            } // if

            /*
             * We capture the output so we can ask imagejpeg() to
             * output the image to the standard output stream
             */
            ob_start();
            imagejpeg($tmpImg);
            $imageString = ob_get_clean();
            imagedestroy($tmpImg);
        } // if

        return $imageString;
    }

    // convertBmpImageStringToJpeg

    /*
     * We cannot handle BMP files per default, so we
     * convet BMP files to JPEG
     */
    private function bmp2gd($src, $dest = false)
    {
        /*** try to open the file for reading ***/
        if (!($src_f = fopen($src, 'rb'))) {
            return false;
        } // if

        /*** try to open the destination file for writing ***/
        if (!($dest_f = fopen($dest, 'wb'))) {
            return false;
        } // if

        /*** grab the header ***/
        $header = unpack('vtype/Vsize/v2reserved/Voffset', fread($src_f, 14));

        /*** grab the rest of the image ***/
        $info = unpack(
            'Vsize/Vwidth/Vheight/vplanes/vbits/Vcompression/Vimagesize/Vxres/Vyres/Vncolor/Vimportant',
            fread($src_f, 40)
        );

        /*** extract the header and info into variables ***/
        extract($info);
        extract($header);

        /*** check for BMP signature ***/
        if ($type != 0x4D42) {
            return false;
        } // if

        /*** set the pallete ***/
        $palette_size = $offset - 54;
        $ncolor = $palette_size / 4;
        $gd_header = '';

        /*** true-color vs. palette ***/
        $gd_header .= ($palette_size == 0) ? "\xFF\xFE" : "\xFF\xFF";
        $gd_header .= pack('n2', $width, $height);
        $gd_header .= ($palette_size == 0) ? "\x01" : "\x00";
        if ($palette_size) {
            $gd_header .= pack('n', $ncolor);
        } // if

        /*** we do not allow transparency ***/
        $gd_header .= "\xFF\xFF\xFF\xFF";

        /*** write the destination headers ***/
        fwrite($dest_f, $gd_header);

        /*** if we have a valid palette ***/
        if ($palette_size) {
            /*** read the palette ***/
            $palette = fread($src_f, $palette_size);
            /*** begin the gd palette ***/
            $gd_palette = '';
            $j = 0;
            /*** loop of the palette ***/
            while ($j < $palette_size) {
                $b = $palette[$j++];
                $g = $palette[$j++];
                $r = $palette[$j++];
                $a = $palette[$j++];
                /*** assemble the gd palette ***/
                $gd_palette .= "$r$g$b$a";
            }
            /*** finish the palette ***/
            $gd_palette .= str_repeat("\x00\x00\x00\x00", 256 - $ncolor);
            /*** write the gd palette ***/
            fwrite($dest_f, $gd_palette);
        } // if

        /*** scan line size and alignment ***/
        $scan_line_size = (($bits * $width) + 7) >> 3;
        $scan_line_align = ($scan_line_size & 0x03) ? 4 - ($scan_line_size & 0x03) : 0;

        /*** this is where the work is done ***/
        for ($i = 0, $l = $height - 1; $i < $height; $i++, $l--) {
            /*** create scan lines starting from bottom ***/
            fseek($src_f, $offset + (($scan_line_size + $scan_line_align) * $l));
            $scan_line = fread($src_f, $scan_line_size);
            if ($bits == 24) {
                $gd_scan_line = '';
                $j = 0;
                while ($j < $scan_line_size) {
                    $b = $scan_line[$j++];
                    $g = $scan_line[$j++];
                    $r = $scan_line[$j++];
                    $gd_scan_line .= "\x00$r$g$b";
                }
            } elseif ($bits == 8) {
                $gd_scan_line = $scan_line;
            } elseif ($bits == 4) {
                $gd_scan_line = '';
                $j = 0;
                while ($j < $scan_line_size) {
                    $byte = ord($scan_line[$j++]);
                    $p1 = chr($byte >> 4);
                    $p2 = chr($byte & 0x0F);
                    $gd_scan_line .= "$p1$p2";
                } // while
                $gd_scan_line = substr($gd_scan_line, 0, $width);
            } elseif ($bits == 1) {
                $gd_scan_line = '';
                $j = 0;
                while ($j < $scan_line_size) {
                    $byte = ord($scan_line[$j++]);
                    $p1 = chr((int) (($byte & 0x80) != 0));
                    $p2 = chr((int) (($byte & 0x40) != 0));
                    $p3 = chr((int) (($byte & 0x20) != 0));
                    $p4 = chr((int) (($byte & 0x10) != 0));
                    $p5 = chr((int) (($byte & 0x08) != 0));
                    $p6 = chr((int) (($byte & 0x04) != 0));
                    $p7 = chr((int) (($byte & 0x02) != 0));
                    $p8 = chr((int) (($byte & 0x01) != 0));
                    $gd_scan_line .= "$p1$p2$p3$p4$p5$p6$p7$p8";
                }
                /*** put the gd scan lines together ***/
                $gd_scan_line = substr($gd_scan_line, 0, $width);
            } else {
                return false;
            } // else
            /*** write the gd scan lines ***/
            fwrite($dest_f, $gd_scan_line);
        } // for

        /*** close the source file ***/
        fclose($src_f);
        /*** close the destination file ***/
        fclose($dest_f);

        return true;
    }

    // bmp2gd
} // Services_Image_BmpConverter