Page 553 - Beginning PHP 5.3

Chapter 17: Generating Images with PHP

Drawing Circles and Ellipses
To draw circles and ellipses in PHP, use the imageellipse() function. It works differently from
the imagerectangle() and imageline() functions, in that you do not provide the outer limits of the
shape. Rather, you describe an ellipse by providing its center point, and then specifying how high and
how wide the ellipse should be.

Here ’ s an example:

imageellipse( $myImage, 90, 60, 160, 50, $myBlack );

This ellipse, shown in Figure 17 - 8, has its center on the pixel at (90,60). The width of the ellipse is 160
pixels and the height is 50 pixels.

To draw a circle, simply describe an ellipse that has the same width and height (see Figure 17 - 9):

imageellipse( $myImage, 90, 60, 70, 70, $myBlack );

Figure 17-8

Figure 17-9

Drawing an Arc
An arc is a partial ellipse — one that doesn ’ t join up. To draw an arc, you call the imagearc() function.

You describe an arc in the same way as an ellipse, except that you need to add two arguments to describe
where the arc starts and ends. You specify the start and end points in degrees (there are 360 degrees in a

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