imagesetthickness()

(PHP 4 >= 4.0.6, PHP 5, PHP 7)

设定画线的宽度

说明

imagesetthickness()把画矩形，多边形，椭圆等等时所用的线宽设为$thickness个像素。成功时返回TRUE，或者在失败时返回FALSE。

Note:此函数需要 GD 2.0.1 或更高版本(推荐 2.0.28 及更高版本)。

参数

由图象创建函数(例如imagecreatetruecolor())返回的图象资源。

Thickness, in pixels.

返回值

成功时返回TRUE，或者在失败时返回FALSE。

范例

imagesetthickness() example

以上例程的输出类似于：

注释

Note:此函数需要 GD 2.0.1 或更高版本(推荐 2.0.28 及更高版本)。

Apparently imagesetthickness doesn't work if antialiasing is set to true.

thanks circle14,
just change the line & see its solved what we need for ellipse 
while ($line 
Note: Also, for me (working under PHP 5.0.2) this function ONLY seems to work with imageline...
The way that imagesetthickness works with imagerectangle() is pretty strange.

This will draw a 41x41 square (because gd need the bottom right pixel, inclusive. 50 should get replaced by 49). This will "work" like:

The second example:

This will draw a 43x43 square because the border (thickness) is set to 2. *however* this is not a "regular" border of 2 pixels around the 41x41 original square! 
On the left and right, there will be a thickness of 3, while there we be a thickness of 2.
If you take the imageline example, but set the thickness before to 2, this will *almost* do the trick: the left most pixel of the square will not be drawn.
To conclude:
1) do not forget that (width, height) of drawn rectangle is (x2-x1+1, y2-y1+1)
2) thickness is bad implemented (or at least, the behavior i s not documented) on rectangle, as the left/right thickness is not the wanted one.
3) 4*imageline() should do the trick, but after "patching" the top left pixel.
One thing worse to mention is that imagesetthikness() works on the next object you draw.
For ex : you can draw a grid within a grapg with a thickness of 1 
by invoking imagesetthickness($image, 1);
... script to draw your grid...
and then invoke imagesetthikness with a draw your graph lines with a thickness of 3
imagesetthickness($image, 3);
... script to draw your graph lines...
Hope this helps...
An easier to manage thickness is, before to draw in the ellipse to play with 2 ellipse with different color :

The first line draw a filled ellipse with the wanted color, and the 2nd one, draw an ellipse with the background color from the same center, but is smaller.
The drawback of this method is that you erase everything in the middle of the ellipse.
Here is a custom function I wrote that addresses the line thickness issues with ellipses :

I hope you find this useful.
As you can see in the example image, the left and right sides are 1 px wider than they should be, this is the case for every width > 1. 
Wrote this function to fix that bit.. probably not a drop-in replacement though. It draws a rectangle *around* the given coordinates, for any width line. 
There is a known bug. Imagesetthickness is NOT working on ellipse.
 

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