CODEWITHSUNDEEP
cocos2d-iphoneccscrollview
Grant Cermak
Grant Cermak

Reputation: 1818

How can I control the size of a CCScrollView?

When using a CCScrollView I would like to be able to limit the viewable area to a certain bounding box. How can this be achieved?

Setting the content size does not affect the viewable area.

Upvotes: 0

Views: 372

Answers (1)

Grant Cermak
Grant Cermak

Reputation: 1818

So I found what seems to be a reasonable way to do this. There was some code on the cocos2d forum for clipping an area using GL_SCISSOR:

http://forum.cocos2d-swift.org/t/cocos2d-3-1-beta-gl-scissor-test/13608/4

-(void)visit:(CCRenderer *)renderer parentTransform:(const GLKMatrix4 *)parentTransform
{
    CGPoint positionInWorldCoords = [self convertToWorldSpace:ccp(0, 0)];
    CGFloat contentScaleFactor = [[CCDirector sharedDirector] contentScaleFactor];

    positionInWorldCoords = ccpMult(positionInWorldCoords, contentScaleFactor);


    [renderer enqueueBlock:^{
        glEnable(GL_SCISSOR_TEST);
        glScissor(positionInWorldCoords.x, positionInWorldCoords.y, self.contentSize.width * contentScaleFactor, self.contentSize.height * contentScaleFactor);
} globalSortOrder:0 debugLabel:nil threadSafe:YES];

    [super visit:renderer parentTransform:parentTransform];

    [renderer enqueueBlock:^{
        glDisable(GL_SCISSOR_TEST);
    } globalSortOrder:0 debugLabel:nil threadSafe:YES];
}

So I subclassed CCScrollView and added this method. I ended up having to tweak the coordinates a bit to get the exact right clipping area. Seems like a clunky answer so I hope someone has a better answer.

Upvotes: 0

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