PHP scales png images to support transparent background

PHP scales png images to support transparent background

PHP scales png images to support transparent background

Function smart_resize_image ($ file, $ width = 0, $ height = 0, $ proportional = false, $ output = 'file', $ delete_original = true, $ use_linux_commands = false)

{

If ($ height <= 0 & $ width <= 0 ){

Return false;

}

$ Info = getimagesize ($ file );

$ Image = '';

$ Final_width = 0;

$ Final_height = 0;

List ($ width_old, $ height_old) = $ info;

If ($ proportional ){

If ($ width = 0) $ factor = $ height/$ height_old;

Elseif ($ height = 0) $ factor = $ width/$ width_old;

Else $ factor = min ($ width/$ width_old, $ height/$ height_old );

$ Final_width = round ($ width_old * $ factor );

$ Final_height = round ($ height_old * $ factor );

}

Else {

$ Final_width = ($ width <= 0 )? $ Width_old: $ width;

$ Final_height = ($ height <= 0 )? $ Height_old: $ height;

}

Switch ($ info [2]) {

Case IMAGETYPE_GIF:

$ Image = imagecreatefromgif ($ file );

Break;

Case IMAGETYPE_JPEG:

$ Image = imagecreatefromjpeg ($ file );

Break;

Case IMAGETYPE_PNG:

$ Image = imagecreatefrompng ($ file );

Break;

Default:

Return false;

}

$ Image_resized = imagecreatetruecolor ($ final_width, $ final_height );

If ($ info [2] = IMAGETYPE_GIF) | ($ info [2] = IMAGETYPE_PNG )){

$ Trnprt_indx = imagecolortransparent ($ image );

// If we have a specific transparent color

If ($ trnprt_indx> = 0 ){

// Get the original image's transparent color's RGB values

$ Trnprt_color = imagecolorsforindex ($ image, $ trnprt_indx );

// Allocate the same color in the new image resource

$ Trnprt_indx = imagecolorallocate ($ image_resized, $ trnprt_color ['red'], $ trnprt_color ['green'], $ trnprt_color ['blue']);

// Completely fill the background of the new image with allocated color.

Imagefill ($ image_resized, 0, 0, $ trnprt_indx );

// Set the background color for new image to transparent

Imagecolortransparent ($ image_resized, $ trnprt_indx );

}

// Always make a transparent background color for PNGs that don't have one allocated already

Elseif ($ info [2] = IMAGETYPE_PNG ){

// Turn off transparency blending (temporarily)

Imagealphablending ($ image_resized, false );

// Create a new transparent color for image

$ Color = imagecolorallocatealpha ($ image_resized, 0, 0, 0,127 );

// Completely fill the background of the new image with allocated color.

Imagefill ($ image_resized, 0, 0, $ color );

// Restore transparency blending

Imagesavealpha ($ image_resized, true );

}

}

Imagecopyresampled ($ image_resized, $ image, 0, 0, 0, 0, $ final_width, $ final_height, $ width_old, $ height_old );

If ($ delete_original ){

If ($ use_linux_commands)

Exec ('rm '. $ file );

Else

@ Unlink ($ file );

}

Switch (strtolower ($ output )){

Case 'browser ':

$ Mime = image_type_to_mime_type ($ info [2]);

Header ("Content-type: $ mime ");

$ Output = NULL;

Break;

Case 'file ':

$ Output = $ file;

Break;

Case 'Return ':

Return $ image_resized;

Break;

Default:

Break;

}

Switch ($ info [2]) {

Case IMAGETYPE_GIF:

Imagegif ($ image_resized, $ output );

Break;

Case IMAGETYPE_JPEG:

Imagejpeg ($ image_resized, $ output );

Break;

Case IMAGETYPE_PNG:

Imagepng ($ image_resized, $ output );

Break;

Default:

Return false;

}

Return true;

}