iOS utility classes for asynchronous rendering and display.
(It was used by YYText)

Simple Usage

@interface YYLabel : UIView
@property NSString *text;
@property UIFont *font;
@end

@implementation YYLabel

- (void)setText:(NSString *)text {
    _text = text.copy;
    [[YYTransaction transactionWithTarget:self selector:@selector(contentsNeedUpdated)] commit];
}

- (void)setFont:(UIFont *)font {
    _font = font;
    [[YYTransaction transactionWithTarget:self selector:@selector(contentsNeedUpdated)] commit];
}

- (void)layoutSubviews {
    [super layoutSubviews];
    [[YYTransaction transactionWithTarget:self selector:@selector(contentsNeedUpdated)] commit];
}

- (void)contentsNeedUpdated {
    // do update
    [self.layer setNeedsDisplay];
}

#pragma mark - YYAsyncLayer

+ (Class)layerClass {
    return YYAsyncLayer.class;
}

- (YYAsyncLayerDisplayTask *)newAsyncDisplayTask {

    // capture current state to display task
    NSString *text = _text;
    UIFont *font = _font;

    YYAsyncLayerDisplayTask *task = [YYAsyncLayerDisplayTask new];
    task.willDisplay = ^(CALayer *layer) {
        //...
    };

    task.display = ^(CGContextRef context, CGSize size, BOOL(^isCancelled)(void)) {
        if (isCancelled()) return;
        NSArray *lines = CreateCTLines(text, font, size.width);
        if (isCancelled()) return;

        for (int i = 0; i < lines.count; i++) {
            CTLineRef line = line[i];
            CGContextSetTextPosition(context, 0, i * font.pointSize * 1.5);
            CTLineDraw(line, context);
            if (isCancelled()) return;
        }
    };

    task.didDisplay = ^(CALayer *layer, BOOL finished) {
        if (finished) {
            // finished
        } else {
            // cancelled
        }
    };

    return task;
}
@end

Installation

Manually

1. Download all the files in the YYAsyncLayer subdirectory.
2. Add the source files to your Xcode project.
3. Import YYAsyncLayer.h.

Documentation

Full API documentation is available on CocoaDocs.
You can also install documentation locally using appledoc.

Requirements

This library requires iOS 6.0+ and Xcode 7.0+.

License

YYAsyncLayer is provided under the MIT license. See LICENSE file for details.

中文介绍

iOS 异步绘制与显示的工具类。
(该工具是从 YYText 提取出来的独立组件)

简单用法

@interface YYLabel : UIView
@property NSString *text;
@property UIFont *font;
@end

@implementation YYLabel

- (void)setText:(NSString *)text {
    _text = text.copy;
    [[YYTransaction transactionWithTarget:self selector:@selector(contentsNeedUpdated)] commit];
}

- (void)setFont:(UIFont *)font {
    _font = font;
    [[YYTransaction transactionWithTarget:self selector:@selector(contentsNeedUpdated)] commit];
}

- (void)layoutSubviews {
    [super layoutSubviews];
    [[YYTransaction transactionWithTarget:self selector:@selector(contentsNeedUpdated)] commit];
}

- (void)contentsNeedUpdated {
    // do update
    [self.layer setNeedsDisplay];
}

#pragma mark - YYAsyncLayer

+ (Class)layerClass {
    return YYAsyncLayer.class;
}

- (YYAsyncLayerDisplayTask *)newAsyncDisplayTask {

    // capture current state to display task
    NSString *text = _text;
    UIFont *font = _font;

    YYAsyncLayerDisplayTask *task = [YYAsyncLayerDisplayTask new];
    task.willDisplay = ^(CALayer *layer) {
        //...
    };

    task.display = ^(CGContextRef context, CGSize size, BOOL(^isCancelled)(void)) {
        if (isCancelled()) return;
        NSArray *lines = CreateCTLines(text, font, size.width);
        if (isCancelled()) return;

        for (int i = 0; i < lines.count; i++) {
            CTLineRef line = line[i];
            CGContextSetTextPosition(context, 0, i * font.pointSize * 1.5);
            CTLineDraw(line, context);
            if (isCancelled()) return;
        }
    };

    task.didDisplay = ^(CALayer *layer, BOOL finished) {
        if (finished) {
            // finished
        } else {
            // cancelled
        }
    };

    return task;
}
@end

安装

手动安装

1. 下载 YYAsyncLayer 文件夹内的所有内容。
2. 将 YYAsyncLayer 内的源文件添加(拖放)到你的工程。
3. 导入 YYAsyncLayer.h。

文档

你可以在 CocoaDocs 查看在线 API 文档，也可以用 appledoc 本地生成文档。

系统要求

该项目最低支持 iOS 6.0 和 Xcode 7.0。

许可证

YYAsyncLayer 使用 MIT 许可证，详情见 LICENSE 文件。

相关文章

iOS 保持界面流畅的技巧