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While writing code, anything I struggle with (and ultimatily figure out, duh) will go here, so others can learn from my trails

Selection Rectangle:

Put in: 2/18/11

This came from the rewrite of the comic helper. Basically I wanted a CALayer to act as a selection rectangle, so using code from Sketch (the example OS X program) I finally got it right. My biggest issue was using bounds instead of frame.

- (CALayer*) hitTestPoint: (NSPoint)locationInWindow offset: (CGPoint*)outOffset { // I copied this from other sources, I didn't create them CGPoint where = NSPointToCGPoint([self convertPoint: locationInWindow fromView: nil]); where = [self.layer convertPoint: where fromLayer: self.layer]; CALayer *layer = [self.layer hitTest: where]; if ( layer != self.layer ){ CGPoint bitPos = [self.layer convertPoint: layer.position fromLayer: layer.superlayer]; if( outOffset ) *outOffset = CGPointMake( bitPos.x-where.x, bitPos.y-where.y); return layer; } else return nil; } CGRect SKTRectFromPoints(NSPoint point1, CGPoint point2) { // I copied this from other sources, I didn't create them return NSRectToCGRect(NSMakeRect(((point1.x <= point2.x) ? point1.x : point2.x), ((point1.y <= point2.y) ? point1.y : point2.y), ((point1.x <= point2.x) ? point2.x - point1.x : point1.x - point2.x), ((point1.y <= point2.y) ? point2.y - point1.y : point1.y - point2.y))); } - (void) mouseDown: (NSEvent*)ev { dragStartPos = ev.locationInWindow; previouslyDraggedLayer = draggingLayer; draggingLayer = [self hitTestPoint: dragStartPos offset: &dragOffset]; // this tells me what i'm clicking on, if anything if ( draggingLayer ){ // make the layer highlight in some way. I put a border around it draggingLayer.zPosition = 100; draggingLayer.shadowOffset = CGSizeMake(3, -3); draggingLayer.shadowOpacity = 0.7; draggingLayer.borderWidth = 2.0; draggingLayer.borderColor = CGColorCreateGenericRGB(0,0,1,1); } else { // I have hit nothing, let's make a selection rectangle CGPoint curPoint; dragStartPos = [self convertPoint:dragStartPos fromView:nil]; if ( !dragRectangle ){ // I tried to set this up in initWithFrame but half the time it didn't show up. This is more "lazy" anyway, setting it up // when you need it makes the app launch a litle faster anyway dragRectangle = [[CALayer alloc] init]; [dragRectangle retain]; // with garbage collection, I probably don't need this, but better to have it [self.layer addSublayer:dragRectangle]; } previouslyDraggedLayer.borderWidth = 0; [CATransaction flush]; // standard "don't animate what I'm about to do stuff [CATransaction begin]; [CATransaction setValue:(id)kCFBooleanTrue forKey:kCATransactionDisableActions]; dragRectangle.backgroundColor = CGColorCreateGenericRGB(.7,.8,.9,.5); // as close as I can come to Apple's colors dragRectangle.borderWidth = 1; dragRectangle.borderColor = CGColorCreateGenericRGB(.1,.2,1,.5); dragRectangle.zPosition = 100; dragRectangle.position = NSPointToCGPoint(dragStartPos); dragRectangle.hidden = NO; dragRectangle.frame = CGRectMake(0,0,1,1); // make a tiny thing to start [CATransaction commit]; while ([ev type] != NSLeftMouseUp) { // and then do it until I release the mouse. //NSLog (@"trying to drag"); ev = [[self window] nextEventMatchingMask:(NSLeftMouseDraggedMask | NSLeftMouseUpMask)]; curPoint = NSPointToCGPoint([self convertPoint:[ev locationInWindow] fromView:nil]); // I'm in a scroll view, so get where I really am [CATransaction flush]; [CATransaction begin]; [CATransaction setValue:(id)kCFBooleanTrue forKey:kCATransactionDisableActions]; dragRectangle.frame = SKTRectFromPoints(dragStartPos, curPoint); // and finally make the rectangle [CATransaction commit]; // here's where you'll put your code to see if you actually hit something } dragRectangle.hidden = YES; // the mouse has been released, hide the rectangle } }

Multiple CALayer Dragging via 1 selection:

Put in: 2/19/11

Here's how I finally got multiple CALayers to drag simultaniously when I dragged one with the mouse. In other words, after using the selection rectangle code above to capture which elements on the page I wanted to move, move them all and keep them in their relitive positions as the first one moves.

in mousedown, add this to the code above, right after the draggingLayer= line: dragStartPos = ev.locationInWindow; dragStartPos = [self convertPoint: dragStartPos fromView: nil]; // this corrects the offset for any others past the first dragStartPos.x += dragOffset.x; // without these three lines, any other ones being dragged jumped just a little when first dragStartPos.y += dragOffset.y; // being dragged but not any after that. then in mouseDragged: NSPoint pos = ev.locationInWindow; NSPoint where = [self convertPoint: pos fromView: nil]; where.x += dragOffset.x; where.y += dragOffset.y; for ( CALayer *obj in selectionRectImages ){ //I've put all the CALayers I picked up from the selection rect into this array CGPoint newPos = [obj.superlayer convertPoint: NSPointToCGPoint(where) fromLayer: self.layer]; [CATransaction flush]; [CATransaction begin]; [CATransaction setValue:(id)kCFBooleanTrue forKey:kCATransactionDisableActions]; if ( [obj isEqual:draggingLayer] ){ obj.position = newPos; // it just goes to the new position, no sweat } else { newPos.x = obj.position.x + (newPos.x - dragStartPos.x); // took me so long. Basically the position of this object is where it currently is, plus where the object being newPos.y = obj.position.y + (newPos.y - dragStartPos.y); // dragged is going, minus where the drag started, which is corrected for the offset already obj.position = newPos; } dragStartPos = where; // this is also key, because now when I drag a little more, I have to start the drag from where I ended last time }

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Selection Rectangle:

Multiple CALayer Dragging via 1 selection: