iOS实现文字转化成彩色文字图片

本文写了个将文字转化为多彩图片的功能，输入文字将文字转化为彩色的文字图片，可选择不同的字体，渐变，先看看效果。

实现主要用CAGradientLayer渐变，先看看上部展示实现代码：

-（void）setupContentView{ UIView *contentView = [[UIView alloc] initWithFrame:CGRectMake（0, 44, ScreenWidth, ScreenHight - 44 -300）]; [self.view addSubview:contentView]; UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector（tapGestureAction:）]; [contentView addGestureRecognizer:tapGesture]; self.topContentView = contentView; self.topContentView.backgroundColor = [UIColor clearColor]; UILabel *label = [[UILabel alloc] init]; label.numberOfLines = 0; label.text = @"ABC"; label.frame = [self calculateContextLabelFrameWithTitle:@"ABC"]; label.center = CGPointMake（contentView.bounds.size.width / 2, contentView.bounds.size.height / 2）; label.font = [UIFont fontWithName:self.fontNameArray[0] size:25]; label.textAlignment = NSTextAlignmentCenter; [contentView addSubview:label]; label.backgroundColor = [UIColor clearColor]; self.contentLabel = label; self.gradientLayer = [CAGradientLayer layer]; self.gradientLayer.frame = CGRectMake（label.frame.origin.x, label.frame.origin.y, label.frame.size.width, label.frame.size.height）; self.gradientLayer.backgroundColor = [UIColor clearColor].CGColor; self.gradientLayer.startPoint = CGPointMake（0,0.5）; self.gradientLayer.endPoint = CGPointMake（1,0.5）; self.gradientLayer.colors = self.grandentArr[0]; [contentView.layer addSublayer:self.gradientLayer]; self.gradientLayer.mask = self.contentLabel.layer; self.contentLabel.frame = self.gradientLayer.bounds;}

当输入的文字改变时，重新计算 self.gradientLayer的frame

-（void）textFieldTextChange:（NSNotification*）notice{ self.contentLabel.text = self.textField.text; [self reCalculateGradientLayerFrame];}

下部分的实现代码：

-（void）setupBottomView{ UIView *bottomView =[[UIView alloc] initWithFrame:CGRectMake（0, ScreenHight - 300, ScreenWidth, 300）]; bottomView.backgroundColor = JGCOLOR（222, 222, 222）; [self.view addSubview:bottomView]; self.bottomContentView = bottomView; UIView *textContentView = [[UIView alloc] init]; textContentView.frame = CGRectMake（0, 0, bottomView.bounds.size.width, 50）; [bottomView addSubview:textContentView]; textContentView.backgroundColor = JGCOLOR（55, 44, 16）; UITextField *textField = [[UITextField alloc] init]; textField.borderStyle = UITextBorderStyleRoundedRect; textField.frame = CGRectMake（10, 5, textContentView.bounds.size.width - 20, textContentView.bounds.size.height - 10）; [textContentView addSubview:textField]; self.textField = textField; CGFloat orgY = 60; CGFloat orgx = 10; CGFloat space = 10; CGFloat width = （ScreenWidth - orgx * 2 - 3 * space） / 4; CGFloat height = 35; for （int i = 0; i < 16; i++） {UIView *vw = [[UIView alloc] initWithFrame:CGRectMake（orgx + （i % 4） * width + （i % 4） * space, orgY + （i / 4） * height + （i / 4） * space, width, height）];vw.backgroundColor = [UIColor clearColor];vw.tag = i + 1;[self.bottomContentView addSubview:vw];UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector（viewTap:）];[vw addGestureRecognizer:tapGesture];UILabel *label = [[UILabel alloc] initWithFrame:vw.bounds ];label.textAlignment = NSTextAlignmentCenter;label.text = @"ABC";label.frame = vw.bounds;label.font = [UIFont fontWithName:self.fontNameArray[i % 4] size:25];label.backgroundColor = [UIColor clearColor];[vw addSubview:label];CAGradientLayer *grandient = [CAGradientLayer layer];grandient.frame = CGRectMake（label.frame.origin.x, label.frame.origin.y, label.frame.size.width, label.frame.size.height）;grandient.backgroundColor = [UIColor clearColor].CGColor;grandient.startPoint = CGPointMake（0,0.5）;grandient.endPoint = CGPointMake（1,0.5）;grandient.colors = self.grandentArr[i / 4];[vw.layer addSublayer:grandient];grandient.mask = label.layer;label.frame = grandient.bounds; }}

将文字转化为图片的代码：

-（void）getTitleImg{ UIGraphicsBeginImageContext（self.topContentView.frame.size）; CGContextRef context = UIGraphicsGetCurrentContext（）; if （[[UIDevice currentDevice].systemVersion floatValue] >= 7.0） {[self.topContentView drawViewHierarchyInRect:self.topContentView.frame afterScreenUpdates:YES]; } else {[self.topContentView.layer renderInContext:context]; } UIImage *img = UIGraphicsGetImageFromCurrentImageContext（）; UIGraphicsEndImageContext（）; CGImageRef newImgRef = CGImageCreateWithImageInRect（img.CGImage, CGRectMake（self.gradientLayer.frame.origin.x, self.gradientLayer.frame.origin.y + 44, self.gradientLayer.frame.size.width, self.gradientLayer.frame.size.height））; UIGraphicsBeginImageContextWithOptions（self.gradientLayer.frame.size, NO, [UIScreen mainScreen].scale）; context = UIGraphicsGetCurrentContext（）; CGContextTranslateCTM（context, 0, self.gradientLayer.frame.size.height）; CGContextScaleCTM（context, 1, -1）; CGContextDrawImage（context, CGRectMake（0, 0, self.gradientLayer.frame.size.width, self.gradientLayer.frame.size.height）, newImgRef）; UIImage *newImg = UIGraphicsGetImageFromCurrentImageContext（）; UIGraphicsEndImageContext（）; ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init]; [library toolWriteImageToSavedPhotosAlbum:newImg.CGImage metadata:nil completionBlock:^（NSURL *assetURL, NSError *error） {if （error） { JGLog（@"写入出错"）;} } groupName:@"相册名称"];}

核心代码如上，主要运用到了CAGradientLayer,截图，裁图的方法。
以上就是本文的全部内容，希望对大家的学习有所帮助。