Everyone should pay attention, when learning to make verification codes, we need to open the manual
The function of making verification codes is relatively long
imagecreatetruecolor(); Create a canvas, let’s see below His syntax
Syntax:
resource imagecreatetruecolor (int $width, int $height)
Description: Return a Image identifier, width is $width and height is $height
Returns the image resource after success, returns FALSE after failure.
After we create a canvas, we need to assign a color to the canvas
imagecolorallocate
Syntax:
int imagecolorallocate ( resource $image , int $red , int $green , int $blue );
The first parameter,returns a resource type, and the subsequent parameters are in RGB format Color
How to output the image
header("content-type:image/png");
imagepng($image);
Destroy resources
##imagedestroy($img);
Let’s take a look at the example
Create a canvas and set a color for it
<?php
//第一步 创建一个画布
$image = imagecreatetruecolor(100, 30); //创建一个宽为100高为30的黑色图像
$bgcolor = imagecolorallocate($image, 255, 0, 0); //为图像分配颜色
imagefill($image,0,0,$bgcolor); //给黑色的背景图像分配白色
//输出图像
header("content-type:image/png");
imagepng($image);
//销毁资源
imagedestroy($img);
?>As shown in the above code, we can see that a canvas with a width of 100, a height of 30 and a red background is output
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