Making Usage Statistics in PHP - Creating the Image Library

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Having the data, let's start to deal with the image creation library of PHP (GD). Its output is GIF/PNG/JPEG. It uses image resources.  These are PHP variables representing images. Usually, in a program there is only one image resource. You can create an image resource using one of the following functions:

1. ImageCreate (int width, int height) - Creates a blank image resource
2. ImageCreateTrueColor (int width, int height) - Creates a blank true color image resource
3. ImageCreateFromGIF (string filename) - Creates an image resource using a given picture file
4. ImageCreateFromJPEG (string filename) - Creates an image resource using a given picture file
5. ImageCreateFromPNG (string filename) - Creates an image resource using a given picture file

This code can be good for this, but don't forget to call the header function because it's not HTML output!


header('Content-type: image/png');
$image=imagecreate(400,210); 



Then you can start to draw the picture. Here are some of the functions - read them as we will use some to make the Top 10 stats. For more, see the PHP manual.

1. ImageColorAllocate (resource image, int red, int green, int blue) - Prepares an RGB color to use
2. ImageLine (resource image, int x1, int y1, int x2, int y2, int color) - Draws a line
3. ImageRectangle (resource image, int x1, int y1, int x2, int y2, int col) - Draws a rectangle
4. ImagePolygon (resource image, array points, int num_points, int color) - Draws a polygon using an array
5. ImageFilledRectangle (resource image, int x1, int y1, int x2, int y2, int color) - Draws a filled rectangle
6. ImageTTFText (resource image, int size, int angle, int x, int y, int color, string fontfile, string text) - Draws a TrueType text

Below you can read the code. It can be a little confusing, especially the numeric expressions, because you have to think in X and Y coordinates. But try it, you'll get the hang of it!

Next: Charting the Results >>
 

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