How to remove image color in php

php method to remove the color of the picture: first create a PHP sample file; then use the "imagecolortransparent($image,imagecolorallocate(...));" method to remove the color in the picture and make it transparent That’s it.

The operating environment of this article: windows7 system, PHP7.1 version, DELL G3 computer

PHP How to remove some colors from a picture, Make it transparent?

Use imagecolortransparent

The first of the two parameters is the picture, and the second is the matching color

The matching color is ImageColorAllocate

Complete demonstration, for example:

imagecolortransparent($image,imagecolorallocate($image,255,255,255));

This is to turn the matched white color into transparent

Function introduction:

For some colors, use a loop to make the matching color transparent

imagecolortransparent — Define a color as transparent.

Syntax

int imagecolortransparent ( resource $image [, int $color ] )

imagecolortransparent() Sets the transparent color in image to color. image is the image identifier returned by imagecreatetruecolor(), and color is the color identifier returned by imagecolorallocate().

Note: Transparent color is an attribute of the image, and transparency is not an attribute of color. Once you set a color to be transparent, any areas in the image that were previously painted that color become transparent.

Returns the identifier of the new transparent color. If color is omitted, returns the identifier of the current transparent color.

Note: Transparency can only be copied via imagecopymerge() and true color images, not imagecopy() or palette images.

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