BitBlt() equivalent in Objective-C/Cocoa

Question

I made a scrolling tile 2D video game in visual basic a few years back. I am translating it to Cocoa for the Mac. Is there a framework that would allow me to use BitBlt? Or is there an equivalent to BitBlt without using OpenGL? Thanks!

Answer 1

You should probably start with Core Graphics

Answer 2

As Matt mentioned, you probably want CGContextDrawImage and CGContextSetBlendMode.

First, you need to create a CGImageRef from the image data. You do this with a data provider. If you already have the image loaded in memory, then you should use CGDataProviderCreateDirect. That data provider will be a parameter to CGImageCreate.

Next, in your Cocoa view's drawRect: method, you'll want to get the current context like this: CGContextRef cgContext = [[NSGraphicsContext currentContext] graphicsPort];

Then use CGContextDrawImage to draw the image.

As Matt mentioned, you can control blending with CGContextSetBlendMode.