将斜角效果添加到UIView

Question

我希望我的按钮看起来像这样.

我问设计师,他说他已经使用了斜面效果,我第一次听到斜角这个词.

我搜索了SO但找不到任何有用的东西.任何帮助表示赞赏.

谢谢.

Answer 1

斜角是“沿着木头、玻璃等边缘的倾斜表面”。在计算世界中，我们通常在按钮周围使用“斜角”，以产生 3D 幻觉。尽管自 iOS7 以来已经出现了一种明显的趋势，那就是更喜欢扁平化的外观。

当您说希望对 UI 视图应用斜角时，您指的是边缘周围的渐变。我在下图中用红色突出显示了这一点。

当您说希望按钮看起来像您的图像时，斜角可能只是该目标的一部分。

正如已经建议的那样，让按钮看起来像这样的最快、最简单的方法是使用按钮的图像，并将其应用到您的视图中。这可能也是更有效的方法。或者，可以使用代码创建按钮。尽管您需要矢量格式的按钮。

为了在代码中生成按钮，您需要向设计人员询问矢量格式的按钮。SVG 格式可能是最简单的。有许多第三方程序可以将矢量图像转换为 Core Graphics 代码。对于此示例，我使用了一个名为 Graphic（由 Autodesk 提供）的程序。尽管如此，我必须修复其生成代码中的一些错误。更新的替代方案可能会更好。我还没有尝试过 Graphic 在 Swift 中生成代码。

这是我的按钮示例，与您的设计类似。此代码是概念证明，因此按钮的大小或位置不是很好。我没有花太长时间将我的按钮与您的确切设计相匹配。但是，它将生成一个包含类似按钮的视图。

#import "Button.h"
#import <CoreText/CoreText.h>

@implementation Button

- (void)drawRect:(CGRect)rect {

    // Do any additional setup after loading the view, typically from a nib.

    CGContextRef ctx = UIGraphicsGetCurrentContext();
    // enable the following lines for flipped coordinate systems
    //CGContextTranslateCTM(ctx, 0, self.bounds.size.height);
    //CGContextScaleCTM(ctx, 1, -1);
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    /*  Shape   */
    CGMutablePathRef pathRef = CGPathCreateMutable();
    CGPathMoveToPoint(pathRef, NULL, 251.424, 272.035);
    CGPathAddCurveToPoint(pathRef, NULL, 251.424, 288.189, 238.328, 301.285, 222.174, 301.285);
    CGPathAddCurveToPoint(pathRef, NULL, 206.02, 301.285, 192.924, 288.189, 192.924, 272.035);
    CGPathAddCurveToPoint(pathRef, NULL, 192.924, 255.881, 206.02, 242.785, 222.174, 242.785);
    CGPathAddCurveToPoint(pathRef, NULL, 238.328, 242.785, 251.424, 255.881, 251.424, 272.035);
    CGPathCloseSubpath(pathRef);

    /*  Gradient Fill  */
    CGContextSaveGState(ctx);
    CGContextAddPath(ctx, pathRef);
    CGContextClip(ctx);

    CGFloat gradientColors[] = {
        0.549, 0.557, 0.565, 1,
        0, 0, 0, 1 };
    CGFloat gradientLocations[] = { 0, 0.973 };

    CGGradientRef gradientRef = CGGradientCreateWithColorComponents(colorSpace, gradientColors, gradientLocations, 2);
    CGContextDrawLinearGradient(ctx, gradientRef, CGPointMake(201.492, 251.353), CGPointMake(242.857, 292.719), (kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation));
    CGGradientRelease(gradientRef);
    CGContextRestoreGState(ctx);

    CGPathRelease(pathRef);

    /*  Shape 2  */
    CGMutablePathRef pathRef2 = CGPathCreateMutable();
    CGPathMoveToPoint(pathRef2, NULL, 247.069, 272.035);
    CGPathAddCurveToPoint(pathRef2, NULL, 247.069, 285.784, 235.923, 296.93, 222.174, 296.93);
    CGPathAddCurveToPoint(pathRef2, NULL, 208.425, 296.93, 197.279, 285.784, 197.279, 272.035);
    CGPathAddCurveToPoint(pathRef2, NULL, 197.279, 258.286, 208.425, 247.14, 222.174, 247.14);
    CGPathAddCurveToPoint(pathRef2, NULL, 235.923, 247.14, 247.069, 258.286, 247.069, 272.035);
    CGPathCloseSubpath(pathRef2);

    /*  Gradient Fill  */
    CGContextSaveGState(ctx);
    CGContextAddPath(ctx, pathRef2);
    CGContextClip(ctx);

    CGFloat gradientColors2[] = {
        0.165, 0.153, 0.153, 1,
        0, 0, 0, 0.651 };
    CGFloat gradientLocations2[] = { 0.897, 0.991 };

    CGGradientRef gradientRef2 = CGGradientCreateWithColorComponents(colorSpace, gradientColors2, gradientLocations2, 2);
    CGContextDrawRadialGradient(ctx, gradientRef2, CGPointMake(222.174, 272.035), 0, CGPointMake(222.174, 272.035), 24.895, (kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation));
    CGGradientRelease(gradientRef2);
    CGContextRestoreGState(ctx);

    CGPathRelease(pathRef2);

    /*  Text   */
    UIColor *colour = [UIColor colorWithRed:1 green:1 blue:1 alpha:1];
    NSMutableAttributedString *attributedStr = [[NSMutableAttributedString alloc] initWithString:@"STOP"];
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    paragraphStyle.alignment = NSTextAlignmentLeft;
    NSDictionary *textAttribs = @{
                                  NSFontAttributeName: [UIFont fontWithName:@"Helvetica" size:10],
                                  NSForegroundColorAttributeName: colour,
                                  NSParagraphStyleAttributeName: paragraphStyle
                                  };
    [attributedStr setAttributes:textAttribs range:NSMakeRange(0, 4)];


    CGRect textBox = CGRectMake(208.736, 270.375, 28.051, 14);
    CGPathRef textBoxPath = CGPathCreateWithRect(CGRectMake(0, 0, textBox.size.width, textBox.size.height), NULL);
    CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((__bridge CFAttributedStringRef)attributedStr);
    CTFrameRef frameRef = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), textBoxPath, NULL);
    CGContextSaveGState(ctx);
    CGContextTranslateCTM(ctx, textBox.origin.x, textBox.origin.y);

    CGContextSetTextMatrix(ctx, CGAffineTransformIdentity);
    CGContextTranslateCTM(ctx, 0.0, textBox.size.height);
    CGContextScaleCTM(ctx, 1.0, -1.0);
    CTFrameDraw(frameRef, ctx);

    CGContextRestoreGState(ctx);
    CGPathRelease(textBoxPath);
    CFRelease(framesetter);
    CFRelease(frameRef);

    /*  Shape 3  */
    CGMutablePathRef pathRef3 = CGPathCreateMutable();
    CGPathMoveToPoint(pathRef3, NULL, 229.861, 260.812);
    CGPathAddCurveToPoint(pathRef3, NULL, 229.861, 262.987, 228.098, 264.75, 225.923, 264.75);
    CGPathAddLineToPoint(pathRef3, NULL, 218.423, 264.75);
    CGPathAddCurveToPoint(pathRef3, NULL, 216.248, 264.75, 214.485, 262.987, 214.485, 260.812);
    CGPathAddLineToPoint(pathRef3, NULL, 214.485, 260.812);
    CGPathAddCurveToPoint(pathRef3, NULL, 214.485, 258.637, 216.248, 256.874, 218.423, 256.874);
    CGPathAddLineToPoint(pathRef3, NULL, 225.923, 256.874);
    CGPathAddCurveToPoint(pathRef3, NULL, 228.099, 256.875, 229.861, 258.638, 229.861, 260.812);
    CGPathAddLineToPoint(pathRef3, NULL, 229.861, 260.812);
    CGPathCloseSubpath(pathRef3);

    CGContextSetRGBFillColor(ctx, 0.514, 0.773, 0.357, 1);
    CGContextAddPath(ctx, pathRef3);
    CGContextFillPath(ctx);

    CGPathRelease(pathRef3);
    CGColorSpaceRelease(colorSpace);

}


@end