Blurry UILabel as programmatic subview of UITableViewCell contentView

user_19410 0
Viewed 10194

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;
uilabel uiview uitableview colors iphone
9 Answers

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.

user_126060

I ran into this problem myself today, and read somewhere that non-integer values for the origin and size of the UILabel's frame can cause this (I know they're floats, but you know what I mean). There has got to be a more elegant solution, but this quick hack appears to have solved the problem for me:

self.valueLabel.frame = CGRectMake((int) frame.origin.x, (int) frame.origin.y, (int) frame.size.width, (int) frame.size.height);

If you find a better solution, please let me know, I'd love to replace this hack with something a bit more tasteful.

user_2565600

Sometimes the reason for the blurriness you have mentioned can be that labels's frame is beyond the cell frame. Even if you see all of your text you have put inside the label on your cell, the actual label size can be bigger than the cell frame.

To check if that is the reason for the effect you see I would suggest to check/print all the data you have about labels size/location after it is instantiated and than check in the delegate method tableView:heightForRowAtIndexPath: that this fit into the cell height you are returning for the cell. Hope it will help in your case.

user_2566340
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