This is the very simple tutorial. In this tutorial we will see how to draw Circle, Triangle and Rectangle in the iPad.
Step 1: Create a Window base application using template. Give the application name “ThreeViews”.
Step 2: Xcode automatically creates the directory structure and adds essential frameworks to it. You can explore the directory structure to check out the content of the directory.
Step 3: We need to add one UIView file in the project. Select classes-> New File -> Add ->Cocoa Touch Class -> Select Objective C class -> Subclass of -> UIView. Give the class name “CircleView”.
Step 4: Open the ThreeViewsAppDelegate.m file and make the following changes in the file:
CircleView *view = [[CircleView alloc] initWithFrame:[window frame]];
[window addSubview:view];
[view release];
[window makeKeyAndVisible];
}
Step 5: Open the CicleView.m file and make the following changes in the drawRect: method.
CGContextRef contextRef = UIGraphicsGetCurrentContext();
CGContextSetRGBFillColor(contextRef, 0, 0, 255, 0.1);
CGContextSetRGBStrokeColor(contextRef, 0, 0, 255, 0.5);
// Draw a circle (filled)
CGContextFillEllipseInRect(contextRef, CGRectMake(100, 100, 25, 25));
// Draw a circle (border only)
CGContextStrokeEllipseInRect(contextRef, CGRectMake(100, 100, 25, 25));
// Get the graphics context and clear it
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextClearRect(ctx, rect);
// Draw a green solid circle
CGContextSetRGBFillColor(ctx, 0, 255, 0, 1);
CGContextFillEllipseInRect(ctx, CGRectMake(100, 100, 25, 25));
// Draw a yellow hollow rectangle
CGContextSetRGBStrokeColor(ctx, 255, 255, 0, 1);
CGContextStrokeRect(ctx, CGRectMake(195, 195, 60, 60));
// Draw a purple triangle with using lines
CGContextSetRGBStrokeColor(ctx, 255, 0, 255, 1);
CGPoint points[6] = { CGPointMake(100, 200), CGPointMake(150, 250),
CGPointMake(150, 250), CGPointMake(50, 250),
CGPointMake(50, 250), CGPointMake(100, 200) };
CGContextStrokeLineSegments(ctx, points, 6);
}
Step 6: Now compile and run the application in the Simulator.
You can Download SourceCode from here ThreeViews