Your comments have been really helpful. I've done two things to get everything to work:
Firstly, I turned my triangle upside down, and I set alpha for black at 0.7 and for white 0.3. Now it is clear that everything works as it should. Many Thanks. Kevin On 31 Mar 2014, at 20:43, Bill Monk <billm...@mac.com> wrote: > CIPageCurlTransition's inputBacksideImage does work, but its scaling and/or > interaction with the shading image seems under-documented (to me anyway), and > as such, seems to behave oddly... > > But I can definitely get a visible backside image by tweaking your code a > little (using https://gist.github.com/SheffieldKevin/98734). > > (No doubt the list will eat the screenshots I'm about to paste in...) > > First, the shading image needs some transparency, else you get just get a > gray gradient on the back, regardless of the backside image. > > I used: > ---- > CIColor *color0 = [CIColor colorWithRed:1.0 green:1.0 blue:1.0 > alpha:0.5]; > [radialGradientFilter setValue:color0 forKey:@"inputColor0"]; > > CIColor *color1 = [CIColor colorWithRed:0.0 green:0.0 blue:0.0 > alpha:0.5]; > [radialGradientFilter setValue:color1 forKey:@"inputColor1"]; > --- > > Alone, that doesn't appear to do much; just a green gradient on the back > side. That's because > > a) the back side image is getting scaled in weird way. All that's visible of > your triangle image its green background. The red triangle in the center is > "wrapped" so far back behind, it isn't visible at all (this will become > apparent...). > > b) your back side image and target image both have extensive green areas, so > it's difficult to tell them apart where they meet. > > > Different colors on the triangle backside image helps: > ---- > CGColorRef backColor = CGColorCreateGenericRGB(1.0, 0.5, 0.2, 1.0); > // magenta-ish > CGColorRef triangleColor = CGColorCreateGenericRGB(0.7, 0.2, 0.5, 1.0); > // orange-y > --- > > But now the back side is just a magenta gradient. Where's the triangle? Maybe > it's wrapped too far around back to be visible... > > Let's flip it to point upwards, with the point touching the top of the image > and the base the full width of the image: > > ------- > CGPoint trianglePoint1 = CGPointMake( 0, 0 ); > CGPoint trianglePoint2 = CGPointMake( kBoundsRect.size.width, 0); > CGPoint trianglePoint3 = CGPointMake( kBoundsRect.size.width / 2, > kBoundsRect.size.height ); > > <Screen Shot 2014-03-31 at 2.08.23 PM.png> > ------- > > > > > > But hmm: when wrapped onto the backside, still only a magenta area is > visible... > > Let's swap the backside image and the target image (the target is the one > revealed by the curl): > > ---------- > CIImage *inputImage = [CIImage imageWithCGImage:sourceImage]; > [pageCurlFilter setValue:inputImage forKey:@"inputImage"]; > > #define SwapDestAndBack (1) > #if SwapDestAndBack > CGImageRef temp = destinationImage; > destinationImage; > destinationImage = temp; > #endif > > CIImage *inputTargetImage = [CIImage > imageWithCGImage:destinationImage]; > [pageCurlFilter setValue:inputTargetImage forKey:@"inputTargetImage"]; > > CIImage *inputBacksideImage = [CIImage > imageWithCGImage:backsideImage]; > [pageCurlFilter setValue:inputBacksideImage > forKey:@"inputBacksideImage"]; > --------- > > > OK, now that looks like as expected: > > <Screen Shot 2014-03-31 at 1.53.28 PM.png> > > The backside image is gradient red, and its green center visible, just-barely > "wrapped around". And the revealed target is magenta, with its centered > orange triangle. > > > > So, why doesn't the magenta image image work on the backside... > > > Swapping the images back the way you had them originally with the macro > > #define SwapDestAndBack (0) > > and changing your DrawFillTriangleAndCreateImage() to return a backside image > 30% larger than the other two, things look a little more as expected: > > > <Screen Shot 2014-03-31 at 2.24.40 PM.png> > > Now the revealed target image is red, with its green central rect. And the > backside image does show the orange triangle, and a bit of the magenta > background... > > But the backside seems really scaled-up. Well, we scaled it up 30%... but > making it even a tiny bit larger or smaller results in very different > results, such that either only a magenta or orange area is visible at all. > > There seems to be *lots* of interaction with the inputRectangle of the crop > filter producing the shadingImage. That may be the key... > > That was all I had time to tweak, but hopefully it'll help a bit. > > > _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
