PHP convert picture format to JPG and automatically scale to the specified size _php tutorial

Recently to a friend to modify the site, to help guests of the small to find some of the site's image is a PNG format, and the picture file is very large, almost all over 200KB, and the same pixel jpg pictures will be much smaller, so in the Internet to find a tutorial, PHP now converts the specified image format to JPG and automatically scales to a specified size to support JPG, BMP, PNG, and GIF formats.

Do not say anything else, directly on the code, this code can not be copied directly to your site to use, you need to know some PHP knowledge, if you do not understand PHP, it is recommended to read the Fire supply PHP Chinese manual.

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function Imagecreatefrombmp ($filename)
{
if (! $f 1 = fopen ($filename, "RB")) return FALSE;

$FILE = Unpack ("Vfile_type/vfile_size/vreserved/vbitmap_offset", Fread ($f 1, 14));
if ($FILE [' file_type ']! = 19778) return FALSE;

$BMP = Unpack (' Vheader_size/vwidth/vheight/vplanes/vbits_per_pixel '. '/vcompression/vsize_bitmap/vhoriz_resolution '.
'/vvert_resolution/vcolors_used/vcolors_important ', fread ($f 1, 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;

$PALETTE = Array ();
if ($BMP [' Colors '] < 16777216)
{
$PALETTE = Unpack (' V '. $BMP [' colors '], fread ($f 1, $BMP [' colors '] * 4));
}

$IMG = Fread ($f 1, $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 '];
}

Fclose ($f 1);
return $res;
}

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function Imagetojpg ($srcFile, $dstFile, $towidth, $toheight)
{
$quality = 80;
$data = @GetImageSize ($srcFile);
Switch ($data [' 2 '])
{

Case 1:

$im = Imagecreatefromgif ($srcFile);
Break
Case 2:

$im = Imagecreatefromjpeg ($srcFile);
Break
Case 3:
$im = Imagecreatefrompng ($srcFile);

Break

Case 6:

$im = Imagecreatefrombmp ($srcFile);

Break
}

$dstX = $srcW = @ImageSX ($im);

$dstY = $srcH = @ImageSY ($im);

$srcW = @ImageSX ($im);
$srcH = @ImageSY ($im);
$dstX = $towidth;
$dstY = $toheight;

$ni = @imageCreateTrueColor ($dstX, $dstY);

@ImageCopyResampled ($ni, $im, 0,0,0,0, $dstX, $dstY, $srcW, $srcH);
@ImageJpeg ($ni, $dstFile, $quality);
@imagedestroy ($im);
@imagedestroy ($ni);

}



Usage:

Imagetojpg (' source filename ', ' target filename ', target width, target high);

?>

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