CODEWITHSUNDEEP
core-graphicsswift3cgcontextcore-foundation
Alex Chu
Alex Chu

Reputation: 31

How to use CFDictionaryCreate in Swift 3?

I want to draw an attributed string with clipping rect, and I found a function written in Objective-C, 

CFDictionaryRef PINCHFrameAttributesCreateWithClippingRect(CGRect clippingRect, CGAffineTransform transform)
{
    CGPathRef clipPath = CGPathCreateWithRect(clippingRect, &transform);

    CFDictionaryRef options;

    CFStringRef keys[] = {kCTFramePathClippingPathAttributeName};
    CFTypeRef values[] = {clipPath};
    CFDictionaryRef clippingPathDict = CFDictionaryCreate(NULL,
                                                          (const void **)&keys, (const void **)&values,
                                                          sizeof(keys) / sizeof(keys[0]),
                                                          &kCFTypeDictionaryKeyCallBacks,
                                                          &kCFTypeDictionaryValueCallBacks);

    CFTypeRef clippingArrayValues[] = { clippingPathDict };
    CFArrayRef clippingPaths = CFArrayCreate(NULL, (const void **)clippingArrayValues, sizeof(clippingArrayValues) / sizeof(clippingArrayValues[0]), &kCFTypeArrayCallBacks);

    CFStringRef optionsKeys[] = {kCTFrameClippingPathsAttributeName};
    CFTypeRef optionsValues[] = {clippingPaths};
    options = CFDictionaryCreate(NULL, (const void **)&optionsKeys, (const void **)&optionsValues,
                                 sizeof(optionsKeys) / sizeof(optionsKeys[0]),
                                 &kCFTypeDictionaryKeyCallBacks,
                                 &kCFTypeDictionaryValueCallBacks);

    CFRelease(clippingPathDict);
    CFRelease(clippingPaths);
    CGPathRelease(clipPath);

    return options;
}

But I failed to translate it in Swift 3, anybody can help me?

// I tried belowing codes, it compiles and run, but text doesn't do clip:

    let keys: [CFString] = [kCTFrameClippingPathsAttributeName]
    let values: [CFTypeRef] = [clipPath]

    let keysPointer = UnsafeMutablePointer<UnsafeRawPointer?>.allocate(capacity: keys.count)
    keysPointer.initialize(to: keys)

    let valuesPointer = UnsafeMutablePointer<UnsafeRawPointer?>.allocate(capacity: values.count)
    valuesPointer.initialize(to: values)

    let options = CFDictionaryCreate(kCFAllocatorDefault, keysPointer, valuesPointer, 1, nil, nil)

    let framesetter = CTFramesetterCreateWithAttributedString(attributedSring)
    let frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, attributedSring.length), rectPath.cgPath, options)
    CTFrameDraw(frame, context)

Upvotes: 3

Views: 2195

Answers (1)

Aleks N.
Aleks N.

Reputation: 6247

Construct a Swift dictionary and then cast it to CFDictionary. Example:

let d = [
        kCGImageSourceShouldAllowFloat as String : true as NSNumber,
        kCGImageSourceCreateThumbnailWithTransform as String : true as NSNumber,
        kCGImageSourceCreateThumbnailFromImageAlways as String : true as NSNumber,
        kCGImageSourceThumbnailMaxPixelSize as String : w as NSNumber
    ] as CFDictionary

More details here: https://bugs.swift.org/browse/SR-2388

Upvotes: 2

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