[Author: justincohen]

Fade to translucent mask used by chrome instead of an ellipses or just truncating the string.

R=dmaclach
APPROVED=dmaclach
DELTA=249  (249 added, 0 deleted, 0 changed)

1 files changed, 115 insertions, 0 deletions

diff --git a/iPhone/GTMFadeTruncatingLabel.m b/iPhone/GTMFadeTruncatingLabel.m
new file mode 100755
index 0000000..619e7bb
--- /dev/null
+++ b/iPhone/GTMFadeTruncatingLabel.m
@@ -0,0 +1,115 @@
+//
+//  GTMFadeTruncatingLabel.m
+//
+//  Copyright 2011 Google Inc.
+//
+//  Licensed under the Apache License, Version 2.0 (the "License"); you may not
+//  use this file except in compliance with the License.  You may obtain a copy
+//  of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+//  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+//  License for the specific language governing permissions and limitations under
+//  the License.
+//
+#import "GTMFadeTruncatingLabel.h"
+
+@interface GTMFadeTruncatingLabel ()
+- (void)setup;
+- (UIImage*)getLinearGradient:(CGRect)rect;
+@end
+
+@implementation GTMFadeTruncatingLabel
+
+@synthesize truncateMode = truncateMode_;
+
+- (void)setup {
+  self.backgroundColor = [UIColor clearColor];
+  truncateMode_ = GTMFadeTruncatingTail;
+}
+
+- (id)initWithFrame:(CGRect)frame {
+  self = [super initWithFrame:frame];
+  if (self) {
+    [self setup];
+  }
+  return self;
+}
+
+- (void)awakeFromNib {
+  [self setup];
+}
+
+// Draw fade gradient mask if text is wider than rect.
+- (void)drawTextInRect:(CGRect)requestedRect {
+  CGContextRef context = UIGraphicsGetCurrentContext();
+  CGContextSaveGState(context);
+
+  CGSize size = [self.text sizeWithFont:self.font];
+  if (size.width > requestedRect.size.width) {
+    UIImage* image = [self getLinearGradient:requestedRect];
+    CGContextClipToMask(context, self.bounds, image.CGImage);
+  }
+
+  CGContextSetFillColorWithColor(context, self.textColor.CGColor);
+  [self.text drawInRect:requestedRect
+               withFont:self.font
+          lineBreakMode:UILineBreakModeClip
+              alignment:self.textAlignment];
+
+  CGContextRestoreGState(context);
+}
+
+// Create gradient opacity mask based on direction.
+- (UIImage*)getLinearGradient:(CGRect)rect {
+  // Create an opaque context.
+  CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray();
+  CGContextRef context = CGBitmapContextCreate (NULL,
+                                                rect.size.width,
+                                                rect.size.height,
+                                                8,
+                                                4*rect.size.width,
+                                                colorSpace,
+                                                kCGImageAlphaNone);
+
+  // White background will mask opaque, black gradient will mask transparent.
+  CGContextSetFillColorWithColor(context, [UIColor whiteColor].CGColor);
+  CGContextFillRect(context, rect);
+
+  // Create gradient from white to black.
+  CGFloat locs[2] = { 0.0f, 1.0f };
+  CGFloat components[4] = { 1.0f, 1.0f, 0.0f, 1.0f };
+  CGGradientRef gradient =
+      CGGradientCreateWithColorComponents(colorSpace, components, locs, 2);
+  CGColorSpaceRelease(colorSpace);
+
+  // Draw head and/or tail gradient.
+  CGFloat fadeWidth = MIN(rect.size.height * 2, floor(rect.size.width / 4));
+  CGFloat minX = CGRectGetMinX(rect);
+  CGFloat maxX = CGRectGetMaxX(rect);
+  if (self.truncateMode & GTMFadeTruncatingTail) {
+    CGFloat startX = maxX - fadeWidth;
+    CGPoint startPoint = CGPointMake(startX, CGRectGetMidY(rect));
+    CGPoint endPoint = CGPointMake(maxX, CGRectGetMidY(rect));
+    CGContextDrawLinearGradient(context, gradient, startPoint, endPoint, 0);
+  }
+  if (self.truncateMode & GTMFadeTruncatingHead) {
+    CGFloat startX = minX + fadeWidth;
+    CGPoint startPoint = CGPointMake(startX, CGRectGetMidY(rect));
+    CGPoint endPoint = CGPointMake(minX, CGRectGetMidY(rect));
+    CGContextDrawLinearGradient(context, gradient, startPoint, endPoint, 0);
+  }
+  CGGradientRelease(gradient);
+
+  // Clean up, return image.
+  CGImageRef ref = CGBitmapContextCreateImage(context);
+  UIImage* image = [UIImage imageWithCGImage:ref];
+  CGImageRelease(ref);
+  CGContextRelease(context);
+  return image;
+}
+
+@end