IOS-将长文字转化成图片方法

我们在看微博时，会看到一些长图片上的显示文章，现在就介绍下如何实现。分析下还是很简单的，总结如下：1、计算文字区域的高 2、利用UIGraphics图形上下文方法来实现 3、验证方法：UIImageWriteToSavedPhotosAlbum，在本地相册中查看成功与否。

-(UIImage *)imageFromText:(NSArray*) arrContent withFont: (CGFloat)fontSize

{

    // set the font type and size

    UIFont *font = [UIFont systemFontOfSize:fontSize];

    NSMutableArray *arrHeight = [[NSMutableArray alloc] initWithCapacity:arrContent.count];

    

    CGFloat fHeight = 0.0f;

    for (NSString *sContent in arrContent) {

        CGSize stringSize = [sContent sizeWithFont:font constrainedToSize:CGSizeMake(CONTENT_MAX_WIDTH, 10000) lineBreakMode:UILineBreakModeWordWrap];

        [arrHeight addObject:[NSNumber numberWithFloat:stringSize.height]];

        fHeight += stringSize.height;

    }

    

    CGSize newSize = CGSizeMake(CONTENT_MAX_WIDTH+20, fHeight+50);

    

    UIGraphicsBeginImageContextWithOptions(newSize,NO,0.0);

    CGContextRef ctx = UIGraphicsGetCurrentContext();

    CGContextSetCharacterSpacing(ctx, 10);

    CGContextSetTextDrawingMode (ctx, kCGTextFillStroke);

    CGContextSetRGBFillColor (ctx, 0.1, 0.2, 0.3, 1); // 6

    CGContextSetRGBStrokeColor (ctx, 0, 0, 0, 1);

    

    int nIndex = 0;

    CGFloat fPosY = 20.0f;

    for (NSString *sContent in arrContent) {

        NSNumber *numHeight = [arrHeight objectAtIndex:nIndex];

        CGRect rect = CGRectMake(10, fPosY, CONTENT_MAX_WIDTH , [numHeight floatValue]);

        [sContent drawInRect:rect withFont:font lineBreakMode:UILineBreakModeWordWrap alignment:UITextAlignmentLeft];

        

        fPosY += [numHeight floatValue];

        nIndex++;

    }

    // transfer image

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);

    return image;

    

}