ios - Cutting an image to a CALayers content during an animation -

i have created subclass of calayer draw slice of pie chart custom color (color), startangle (actualstartangle), endangle (actualendangle) , image (image)[this image should in middle of slice] animating not possible normal cashapelayer. layer drawn this:

- (void)drawincontext:(cgcontextref)ctx{     cgcontextbeginpath(ctx);      cgcontextmovetopoint(ctx, self.center.x, self.center.y);     cgcontextaddarc(ctx, self.center.x, self.center.y, self.radius, self.actualendangle, self.actualstartangle, yes);      cgcontextclosepath(ctx);      cgcontextsetfillcolorwithcolor(ctx, self.color);     cgcontextsetlinewidth(ctx, 0);      cgcontextdrawpath(ctx, kcgpathfillstroke);      if (self.image) {         cgcontextdrawimage(ctx, [self getframeforimglayerwithstartangle:self.actualstartangle andendangle:self.actualendangle], self.image);     } } 

these individual slices animated by:

[catransaction begin];  cabasicanimation *coloranimation = [cabasicanimation animationwithkeypath:@"color"]; coloranimation.timingfunction = [camediatimingfunction functionwithname:kcamediatimingfunctioneaseineaseout]; coloranimation.duration = duration; coloranimation.fromvalue = (id)self.color; coloranimation.tovalue = (id)colortu.cgcolor;  cabasicanimation *startangleanimation = [cabasicanimation animationwithkeypath:@"actualstartangle"]; startangleanimation.timingfunction = [camediatimingfunction functionwithname:kcamediatimingfunctioneaseineaseout]; startangleanimation.duration = duration; startangleanimation.fromvalue = [self valueforkey:@"actualstartangle"]; startangleanimation.tovalue = [[nsnumber alloc] initwithfloat:newstartangle];  cabasicanimation *endangleanimation = [cabasicanimation animationwithkeypath:@"actualendangle"]; endangleanimation.timingfunction = [camediatimingfunction functionwithname:kcamediatimingfunctioneaseineaseout]; endangleanimation.duration = duration; endangleanimation.fromvalue = [self valueforkey:@"actualendangle"]; endangleanimation.tovalue = [[nsnumber alloc] initwithfloat:newendangle];  if (completionblock) {     [catransaction setcompletionblock:completionblock]; }  if (colortu && colortu.cgcolor != self.color) {     [self addanimation:coloranimation forkey:@"color"]; } if (newstartangle != self.actualstartangle) {     [self addanimation:startangleanimation forkey:@"actualstartangle"]; } if (newendangle != self.actualendangle) {     [self addanimation:endangleanimation forkey:@"actualendangle"]; }  [catransaction commit]; 

the problem have image take space individual layer takes (resp. shape in it). solved in general method:

- (bool)imagefitsintoslicewithstartangle:(float)sa andendangle:(float)ea{     bool fits = yes;     cgrect recttouse = [self getframeforimglayerwithstartangle:sa andendangle:ea];      uibezierpath *path = [uibezierpath bezierpath];     [path movetopoint:self.center];     [path addarcwithcenter:self.center radius:self.deg startangle:sa endangle:ea clockwise:yes];     (int w = 0; w <= 1; w++) {         if (fits) {             (int h = 0; h <= 1; h++) {                 if (![path containspoint:cgpointmake(recttouse.origin.x + recttouse.size.width * w, recttouse.origin.y + recttouse.size.height * h)]) {                     fits = no;                     break;                 }             }         }     }     return fits; } 

the problem may fit in end , not @ beginning of animation, have cut image big slice when happens.

i have tried following:

• set mask slice instead of drawing directly -> firstly bad coding , have found energy inefficient, created error (expecting model layer not copy) me.

any ideas on how solve issue? (not tried problem in general, don't think should tried above)

thanks

don't know if it'll help, here drawing code pie chart part :

- (void)drawchartwithframe:(cgrect)frame startangle:(cgfloat)startangle endangle:(cgfloat)endangle fillcolor:(uicolor *)fillcolor strokecolor:(uicolor *)strokecolor {      //// oval drawing     cgrect ovalrect = cgrectmake(cgrectgetminx(frame),cgrectgetminy(frame), cgrectgetwidth(frame), cgrectgetheight(frame));     uibezierpath* ovalpath = uibezierpath.bezierpath;     [ovalpath addarcwithcenter: cgpointmake(cgrectgetmidx(ovalrect), cgrectgetmidy(ovalrect)) radius: cgrectgetwidth(ovalrect) / 2 startangle: -(startangle - 25) * m_pi/180 endangle: -(endangle - 93) * m_pi/180 clockwise: yes];     [ovalpath addlinetopoint: cgpointmake(cgrectgetmidx(ovalrect), cgrectgetmidy(ovalrect))];     [ovalpath closepath];ansform ovaltransform = cgaffinetransformmaketranslation(cgrectgetmidx(ovalrect), cgrectgetmidy(ovalrect));     ovaltransform = cgaffinetransformscale(ovaltransform, 1, cgrectgetheight(ovalrect) / cgrectgetwidth(ovalrect));     [ovalpath applytransform: ovaltransform];      [fillcolor setfill];     [ovalpath fill];     [strokecolor setstroke];     ovalpath.linewidth = 1;     [ovalpath stroke]; } 

it's lighter animate real image.