Open Radar

 
We want to use new iOS 14 PencilKit vector capabilities in our app.

However, our current drawing component is always fixed-width. If we use dynamic brush width, like PencilKit has, the drawings would look different on our other platforms, like Web-app.

It would be nice if there was a way to make width of PKInkingTool constant.

I tried swizzling methods like defaultWidthForInkType:, but my swizzled methods are never called.

Example of code below:
@implementation PKInkingTool (Tracking)
+ (void)load {
    [super load];
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        const char *className = [NSStringFromClass(self) UTF8String];
        Class class = objc_getMetaClass(className);
        SEL originalSelector = @selector(defaultWidthForInkType:);
        SEL swizzledSelector = @selector(ed_defaultWidthForInkType:);
        Method originalMethod = class_getClassMethod(class, originalSelector);
        Method swizzledMethod = class_getClassMethod(class, swizzledSelector);
        BOOL didAddMethod =
            class_addMethod(class,
                originalSelector,
                method_getImplementation(swizzledMethod),
                method_getTypeEncoding(swizzledMethod));
        if (didAddMethod) {
            class_replaceMethod(class,
                swizzledSelector,
                method_getImplementation(originalMethod),
                method_getTypeEncoding(originalMethod));
        } else {
            method_exchangeImplementations(originalMethod, swizzledMethod);
        }
}
+ (CGFloat)ed_defaultWidthForInkType:(PKInkType)inkType {
    return 15.0;
}
@end