Android color picker - updating color array

Question

Hi all, I'm trying to create a color picker for Android that looks like a minimalistic version of Gimp's. So, it has a hue slider and a rectangle with saturation/value variants of a color chosen in hue slider.

Question: what is the best way to create the rectangle?

Right now, I'm creating an 200x200 array of pixels, but it takes ~5sec to create and display rectangle with that array. And I need colors in rectangle to change whenever I change the value in hue slider...

Rectangle is bitmap, btw. Can I use color matrices on that and how? Any examples?

Thanks in advance!

Answer 1

One possibility is to pre-create the rectangles on your developer PC for each slider position, embed them as resources, and then swap in the right one when the slider changes. This may make for a portly application, but it will be nice and quick.

I have not dealt with the 2D graphics API much, so I don't know if there are other possibilities (e.g., color matrices).

Answer 2

OpenIntents has a very nice color picker you can use. It can be installed as an independent app and launched with Intents.

• Code: http://code.google.com/p/openintents/source/browse/#svn/trunk/ColorPicker
• Screenshots/download: http://www.openintents.org/en/colorpicker
• Intent specification: http://www.openintents.org/en/node/670

Answer 3

You can create the rectangle with saturation/value variants that change according to the selected hue, by drawing the rectangle with LinearGradients.

You can incorporate the code here: http://code.google.com/p/android-color-picker/ into your application. Seems that this is what you want.