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Modifying Existing Images

The process of creating images from other images follows the same essential steps as creating a new image—the difference lies in what acts as the image canvas. Previously, you created a new canvas using the ImageCreate() function. When creating an image from a new image, you use the ImageCreateFrom*() family of functions.

You can create images from existing GIFs, JPEGs, PNGs, and plenty of other image types. The functions used to create images from these formats are called ImageCreateFromGif(), ImageCreateFromJpg(), ImageCreateFromPng(), and so forth. In the next example, you can see how easy it is to create a new image from an existing one. The base image is shown in Figure 13.5.

Figure 13.5. The base image.

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