Transparent « graphics « iPhone iPad Media Q&A

1. iPhone SDK: How to Draw a Rounded Rectangle With a Semi-Transparent Gradient and a Drop Shadow    stackoverflow.com

I'm experimenting with drawing on the iPhone by manually creating parts of the UI for my application (In this case a graph). Essentially, I want to draw a rectangle with rounded ...

2. Two images intersection transparency    stackoverflow.com

There are two images. image1 and image2. I have added image2 on image1. Overall the output image must be image1 only but, the portion of the image2 must become transparent. I ...

3. How to Darken an Irregularly Shaped Transparent CALayer on the iPhone?    stackoverflow.com

I'm putting an image into a CALayer that could be irregularly transparent:

 theCardLayer.front = [CALayer layer];
 theCardLayer.front.contents = (id)[cardDrawing CGImage];

4. Core Graphics, how to draw a Rectangle with an ellipse transparency hole?    stackoverflow.com

I am trying to draw a 320x480 rectangle that is hollowed by a ellipse. Imagine drawing a filled rectangle, over the rectangle an filled ellipse, and remove the ellipse from the rectangle, ...

5. Drawing a white color results in a transparent color    stackoverflow.com

So in my custom view, I'm trying to draw a white/gray gradient using Core Graphics. I have the following code:

UIColor *color1 = [UIColor whiteColor];
UIColor *color2 = [UIColor colorWithRed:209.0/255.0 green:212.0/255.0 blue:217.0/255.0 alpha:1.0];

CFMutableArrayRef ...

6. Core Graphics: How to draw overlapped semi transparent rectangle without changing color of the common area    stackoverflow.com

When two semi-transparent overlaps, the part in the middle will combines and blends into a darker color. Is there any way to draw rect as usual, but keep the overlapped part ...