Question

我想为UITableViewCell动态创建一个图像，它基本上是一个带有数字的正方形。方块必须是一种颜色（动态指定），并在其中包含一个数字作为文本。

我查看了CGContextRef文档，但似乎无法弄清楚如何使用指定的特定颜色填充图像。

这是我到目前为止所尝试的。

-(UIImage*)createCellImageWithCount:(NSInteger)cellCount AndColour:(UIColor*)cellColour {

    CGFloat height = IMAGE_HEIGHT;
    CGFloat width = IMAGE_WIDTH;
    UIImage* inputImage;

    UIGraphicsBeginImageContext(CGSizeMake(width, height));
    CGContextRef context = UIGraphicsGetCurrentContext();
    UIGraphicsPushContext(context);

    // drawing code goes here
        // But I have no idea what.

    UIGraphicsPopContext();
    UIImage* outputImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return outImage;
}

Answer 1

首先是第一件事：您不需要推送图形上下文。摆脱UIGraphicsPushContext和UIGraphicsPopContext行。

其次，如何画出你想要的东西：

-(UIImage*)createCellImageWithCount:(NSInteger)cellCount AndColour:(UIColor*)cellColour {

    CGFloat height = IMAGE_HEIGHT;
    CGFloat width = IMAGE_WIDTH;
    UIImage* inputImage;

    UIGraphicsBeginImageContext(CGSizeMake(width, height));
    CGContextRef context = UIGraphicsGetCurrentContext();

    [cellColour set];  // Set foreground and background color to your chosen color
    CGContextFillRect(context,CGRectMake(0,0,width,height));  // Fill in the background
    NSString* number = [NSString stringWithFormat:@"%i",cellCount];  // Turn the number into a string
    UIFont* font = [UIFont systemFontOfSize:12];  // Get a font to draw with.  Change 12 to whatever font size you want to use.
    CGSize size = [number sizeWithFont:font];  // Determine the size of the string you are about to draw
    CGFloat x = (width - size.width)/2;  // Center the string
    CGFloat y = (height - size.height)/2;
    [[UIColor blackColor] set];  // Set the color of the string drawing function
    [number drawAtPoint:CGPointMake(x,y) withFont:font];  // Draw the string

    UIImage* outputImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return outImage;
}

如何动态创建UITableViewCell的图像

1 个答案: