Question

How do I create gradients with ImageMagick in C++?

I am trying to create a visual representation of a WAV file.

I can create an Image with Magick++, draw in the waveform data and save the image as a .png file but it still looks a bit basic.

I’d like to give the image background and waveform gradients but I don’t know how.

Are there any examples of how to create gradients using Magick++?

Many thanks,
Josh

Answer 1

I believe you would have to use the Pixel class and interpolate Colors to create your own gradient fill.

The manual for Magick++ does not indicate that it has native functions for gradient fill.

It may also be possible to use the core ImageMagick API for gradient fill.

Here’s some useful links:

• http://www.imagemagick.org/Usage/canvas/
• http://softwareas.com/imagemagick-one-second-gradient-images

Edit – The Magick Core API does have a DrawGradientImage function which may help you out.

Here’s some more useful links:

• http://www.imagemagick.org/api/MagickCore/struct__GradientInfo.html
• http://www.imagemagick.org/api/MagickCore/index.html
• http://www.imagemagick.org/api/MagickCore/draw_8c_source.html#l03225