Re: UI to allow user to scale and crop image within a circle
Re: UI to allow user to scale and crop image within a circle
- Subject: Re: UI to allow user to scale and crop image within a circle
- From: David Duncan <email@hidden>
- Date: Wed, 24 Feb 2016 10:19:06 -0800
> On Feb 24, 2016, at 4:08 AM, Charles Jenkins <email@hidden> wrote:
>
> Good tip! Thanks, Dave and Quincey. I was pretty sure the problem was something embarrassingly basic.
>
> The next step is to redesign the CircleOverlayView to fill its view with black except for the center of the circle. I already learned that filling the view with black and then filling the circle with clearColor() doesn’t work! My guess is, you do this by adding a mask layer; but you probably don’t redraw the mask in drawRect(), hm? It should never need to be refreshed unless the bounds change.
>
> Assuming I can figure out how to make a mask layer, what is the correct way to monitor for a bounds change in order to recreate the mask?
You can’t fill with clear color with normal blending because clear color has 0 alpha. You can however fill it with the copy blend mode.
>
> --
>
> Charles
>
> On February 24, 2016 at 03:16:00, David Duncan (email@hidden <mailto:email@hidden>) wrote:
>
>>
>> > On Feb 23, 2016, at 7:17 PM, Quincey Morris <email@hidden> wrote:
>> >
>> > On Feb 23, 2016, at 18:50 , Charles Jenkins <email@hidden> wrote:
>> >>
>> >> I draw based on the overlay view’s frame, NOT based on the rect that gets passed in to drawRect(). I must not understand what that parameter is for.
>> >
>> > From the UIView documentation for ‘drawRect’:
>> >
>> >> The portion of the view’s bounds that needs to be updated. The first time your view is drawn, this rectangle is typically the entire visible bounds of your view. However, during subsequent drawing operations, the rectangle may specify only part of your view.
>> >
>> >
>> > So, yes, your code is right now. :)
>> >
>>
>> Its almost right – drawing should be done based on the bounds not the frame (this will be an issue if you either use the frame.origin or if you transform the view).
>>
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>> --
>> David Duncan
--
David Duncan
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