Gradients with colors that have alpha are not rendered correctly anymore. I made a simple project to illustrate that. Just create Objective C project and paste this code inside the ViewController.
`#import <UIKit/UIKit.h>
@interface CustomView : UIView
@property (nonatomic, strong) NSArray<NSNumber *> *colorsArray; // The color components array
// Custom initializer that accepts an NSArray of color components
(instancetype)initWithFrame:(CGRect)frame colors:(NSArray<NSNumber *> *)colorsArray;
@end
@implementation CustomView
// Custom initializer
(instancetype)initWithFrame:(CGRect)frame colors:(NSArray<NSNumber *> *)colorsArray {
self = [super initWithFrame:frame];
if (self) {
_colorsArray = colorsArray; // Store the colors array
}
return self;
}
(void)drawRect:(CGRect)rect {
// Get the current context
CGContextRef context = UIGraphicsGetCurrentContext();
// Convert NSArray to a C-style array of CGFloats
size_t count = self.colorsArray.count;
CGFloat colors[count];
for (size_t i = 0; i < count; i++) {
colors[i] = [self.colorsArray[i] floatValue];
}
// Create a color space
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
// Create the gradient with the passed colors
CGGradientRef gradient = CGGradientCreateWithColorComponents(colorSpace, colors, NULL, count / 4);
// Define the start and end points of the gradient
CGPoint startPoint = CGPointMake(rect.origin.x, rect.origin.y);
CGPoint endPoint = CGPointMake(rect.origin.x, rect.origin.y + rect.size.height);
// Draw the rectangle with the gradient
CGContextSaveGState(context);
CGContextAddRect(context, rect);
CGContextClip(context);
CGContextDrawLinearGradient(context, gradient, startPoint, endPoint, 0);
CGContextRestoreGState(context);
// Release resources
CGGradientRelease(gradient);
CGColorSpaceRelease(colorSpace);
}
@end
@interface ViewController : UIViewController
@end
@implementation ViewController
(void)viewDidLoad {
[super viewDidLoad];
// Get the screen bounds
CGRect screenBounds = [UIScreen mainScreen].bounds;
// Define the size of each custom view
CGFloat customViewWidth = screenBounds.size.width * 0.75;
CGFloat customViewHeight = screenBounds.size.height * 0.75;
// Define a dynamic set of colors for the first custom view (red to blue)
NSArray<NSNumber *> *colorsArray1 = @[
@1.0, @0.0, @0.0, @1.0, // Red
@0.0, @0.0, @1.0, @1.0 // Blue
];
// TODO: This is the bug, there is no transparency
NSNumber *alpha = @0.0;// this is the ***** bug ****
// Define a dynamic set of colors for the second custom view (green to yellow)
NSArray<NSNumber *> *colorsArray2 = @[
@0.0, @1.0, @0.0, alpha, // Green
@1.0, @1.0, @0.0, @1.0 // Yellow
];
// Calculate the position for the first view (centered horizontally and vertically, with slight offset)
CGRect frame1 = CGRectMake((screenBounds.size.width - customViewWidth) / 2 - customViewWidth * 0.25,
(screenBounds.size.height - customViewHeight) / 2 - customViewHeight * 0.25,
customViewWidth, customViewHeight);
CustomView *customView1 = [[CustomView alloc] initWithFrame:frame1 colors:colorsArray1];
// Calculate the position for the second view (slightly shifted from the first view to partially overlap)
CGRect frame2 = CGRectMake((screenBounds.size.width - customViewWidth) / 2 + customViewWidth * 0.25,
(screenBounds.size.height - customViewHeight) / 2 + customViewHeight * 0.25,
customViewWidth, customViewHeight);
CustomView *customView2 = [[CustomView alloc] initWithFrame:frame2 colors:colorsArray2];
// Set autoresizing so they adjust with the screen size
customView1.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
customView2.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
// Add the custom views to the view controller's view
[self.view addSubview:customView1];
[self.view addSubview:customView2];
}
@end`
