模糊UILabel作为UITableViewCell contentView的编程子视图 [英] Blurry UILabel as programmatic subview of UITableViewCell contentView

问题描述

我添加了一个 UILabel 实例作为我的自定义 UITableViewCell 实例的

当我选择单元格时，该行会突出显示为蓝色，除了标签的背景。

当我将标签和内容视图 backgroundColor 设置为 [UIColor clearColor] ，标签文字变得模糊。

如何设置标签背景颜色清楚，允许行

我在其他地方阅读的一个建议是 round

CODE p>

这是我的自定义 UITableViewCell 子视图 -setNeedsLayout 方法：

  UILabel * _objectTitleLabel = [[UILabel alloc] initWithFrame：CGRectNull]; 
 _objectTitleLabel.text = [self.awsObject washedKey]; 
 _objectTitleLabel.font = [UIAppDelegate defaultObjectLabelFont]; 
 _objectTitleLabel.highlightedTextColor = [UIColor clearColor]; // [UIAppDelegate defaultLabelShadowTint]; 
 _objectTitleLabel.backgroundColor = [UIColor clearColor]; // [UIAppDelegate defaultWidgetBackgroundTint]; 
 _objectTitleLabel.frame = CGRectMake（
 kCellImageViewWidth + 2.0 * self.indentationWidth，
 0.5 *（self.tableView.rowHeight  -  1.5 * kCellLabelHeight）+ kCellTitleYPositionNudge，
 contentViewWidth，
 kCellLabelHeight 
）; 
 _objectTitleLabel.frame = CGRectIntegral（_objectTitleLabel.frame）; 
 _objectTitleLabel.tag = kObjectTableViewCellTitleSubviewType; 
 // NSLog（@_ objectTitleLabel：％@，NSStringFromCGRect（_objectTitleLabel.frame））; 
 [self.contentView addSubview：_objectTitleLabel]; 
 [_objectTitleLabel release]，_objectTitleLabel = nil; 
 
 ... 
 
 self.contentView.backgroundColor = [UIAppDelegate defaultWidgetBackgroundTint]; 
 self.contentView.clearsContextBeforeDrawing = YES; 
 self.contentView.autoresizesSubviews = YES; 
 self.contentView.clipsToBounds = YES; 
 self.contentView.contentMode = UIViewContentModeRedraw; 
  

解决方案

问题是子像素渲染，您的原点（这是一个浮点值）具有非零分数分量。四舍五入到最接近的整数，你应该很好。

I am adding a UILabel instance as a subview of my custom UITableViewCell instance's contentView.

When I select the cell, the row is highlighted blue, except for the background of the label. The label text is sharp.

When I set the label and content view backgroundColor property to [UIColor clearColor], the label text becomes blurry.

How do I set the label background color to be clear, to allow the row highlight to come through, while still keeping the label text sharp?

One suggestion I read elsewhere was to round the label's frame values, but this did not have any effect.

CODE

Here is a snippet of my custom UITableViewCell subview's -setNeedsLayout method:

UILabel *_objectTitleLabel = [[UILabel alloc] initWithFrame:CGRectNull];
_objectTitleLabel.text = [self.awsObject cleanedKey];
_objectTitleLabel.font = [UIAppDelegate defaultObjectLabelFont];
_objectTitleLabel.highlightedTextColor = [UIColor clearColor]; //[UIAppDelegate defaultLabelShadowTint];
_objectTitleLabel.backgroundColor = [UIColor clearColor]; //[UIAppDelegate defaultWidgetBackgroundTint];
_objectTitleLabel.frame = CGRectMake(
        kCellImageViewWidth + 2.0 * self.indentationWidth,
        0.5 * (self.tableView.rowHeight - 1.5 * kCellLabelHeight) + kCellTitleYPositionNudge,
        contentViewWidth,
        kCellLabelHeight
);
_objectTitleLabel.frame = CGRectIntegral(_objectTitleLabel.frame);
_objectTitleLabel.tag = kObjectTableViewCellTitleSubviewType;
//NSLog(@"_objectTitleLabel: %@", NSStringFromCGRect(_objectTitleLabel.frame));
[self.contentView addSubview:_objectTitleLabel];
[_objectTitleLabel release], _objectTitleLabel = nil;

...

self.contentView.backgroundColor = [UIAppDelegate defaultWidgetBackgroundTint]; 
self.contentView.clearsContextBeforeDrawing = YES;
self.contentView.autoresizesSubviews = YES;
self.contentView.clipsToBounds = YES;
self.contentView.contentMode = UIViewContentModeRedraw;

解决方案

The issue is sub-pixel rendering, which occurs when your origin (which is a float value) has a non-zero fractional component. Round to the nearest whole number and you should be fine.

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