i developing color selector , using circular gradient , pangesture pick color.
can add crosshair or else current touch position?
i need crosshair visible should not interfere gradient.
this code adds gradient :
- (void)viewdidload { [super viewdidload]; cgsize size = cgsizemake(self.view.bounds.size.width, ((self.view.bounds.size.height)/2)); uigraphicsbeginimagecontextwithoptions(cgsizemake(size.width, size.height), yes, 0.0); [[uicolor whitecolor] setfill]; uirectfill(cgrectmake(0, 0,size.width,size.height)); int sectors = 180; float radius = min(size.width, size.height)/2; float angle = 2 * m_pi/sectors; uibezierpath *bezierpath; ( int = 0; < sectors; i++) { cgpoint center = cgpointmake(((size.width)/2), ((size.height)/2)); bezierpath = [uibezierpath bezierpathwitharccenter:center radius:radius startangle:i * angle endangle:(i + 1) * angle clockwise:yes]; [bezierpath addlinetopoint:center]; [bezierpath closepath]; uicolor *color = [uicolor colorwithhue:((float)i)/sectors saturation:1. brightness:1. alpha:1]; [color setfill]; [color setstroke]; [bezierpath fill]; [bezierpath stroke]; } img = uigraphicsgetimagefromcurrentimagecontext(); gradientview = [[uiimageview alloc]initwithimage:img];; uipangesturerecognizer *pangesture = [[uipangesturerecognizer alloc]initwithtarget:self action:@selector(handlepan:)]; colorview = [[uiview alloc] init]; colorview.frame = cgrectmake(0, 00, 50, 50); rtext.textalignment = nstextalignmentcenter; gtext.textalignment = nstextalignmentcenter; btext.textalignment = nstextalignmentcenter; saturationtext.textalignment = nstextalignmentcenter; alphatext.textalignment = nstextalignmentcenter; brightnesstext.textalignment = nstextalignmentcenter; rtext.keyboardtype = uikeyboardtypenumberpad; gtext.keyboardtype = uikeyboardtypenumberpad; btext.keyboardtype = uikeyboardtypenumberpad; saturationtext.keyboardtype = uikeyboardtypenumberpad; alphatext.keyboardtype = uikeyboardtypenumberpad; brightnesstext.keyboardtype = uikeyboardtypenumberpad; gradientview.frame = cgrectmake(0,0,size.width,size.height); self.view.backgroundcolor = [uicolor whitecolor]; [self.view addsubview:gradientview]; gradientview.userinteractionenabled = yes; [gradientview addgesturerecognizer: pangesture]; [self.view addsubview:colorview]; } the handlepan method :
- (ibaction)handlepan:(uipangesturerecognizer *)sender { if (sender.numberoftouches) { cgsize size = cgsizemake(self.view.bounds.size.width, (self.view.bounds.size.height)/2); float radius = min(size.width, size.height)/2; [alphaslider addtarget:self action:@selector(changeopacity:) forcontrolevents:uicontroleventvaluechanged]; [hellslider addtarget:self action:@selector(changebrightness:) forcontrolevents:uicontroleventvaluechanged]; [saturationslider addtarget:self action:@selector(saturate:) forcontrolevents:uicontroleventvaluechanged]; [rslider addtarget:self action:@selector(redslider:) forcontrolevents:uicontroleventvaluechanged]; [gslider addtarget:self action:@selector(greenslider:) forcontrolevents:uicontroleventvaluechanged]; [bslider addtarget:self action:@selector(blueslider:) forcontrolevents:uicontroleventvaluechanged]; cgpoint lastpoint = [sender locationoftouch: sender.numberoftouches - 1 inview: gradientview]; cgpoint center = cgpointmake((size.width/2), (size.height /2)); cgpoint delta = cgpointmake(lastpoint.x - center.x, lastpoint.y - center.y); cgfloat angle = (delta.y == 0 ? delta.x >= 0 ? 0 : m_pi : atan2(delta.y, delta.x)); angle = fmod(angle, m_pi * 2.0); angle += angle >= 0 ? 0 : m_pi * 2.0; if((lastpoint.x - center.x) + (lastpoint.y - center.y)/2 < radius) { uicolor *color = [uicolor colorwithhue: angle / (m_pi * 2.0) saturation:saturationslider.value brightness:hellslider.value alpha:alphaslider.value]; if ([color getred: &r green: &g blue:&b alpha: &a]) { nslog(@"color value - r : %g g : %g : b %g", r*255, g*255, b*255); } float red = r; float green = g; float blue = b; rtext.text = [nsstring stringwithformat:@"%.0f",rslider.value]; gtext.text = [nsstring stringwithformat:@"%.0f",green*255]; btext.text = [nsstring stringwithformat:@"%.0f",blue*255]; colorview.backgroundcolor = [uicolor colorwithred:(rtext.text.floatvalue/255) green:(gtext.text.floatvalue/255) blue:(btext.text.floatvalue/255) alpha:alphaslider.value]; rslider.value = red*255; gslider.value = green*255; bslider.value = blue*255; alphatext.text = [nsstring stringwithformat:@"%.2f",alphaslider.value]; brightnesstext.text = [nsstring stringwithformat:@"%.2f",hellslider.value]; saturationtext.text = [nsstring stringwithformat:@"%.2f",saturationslider.value]; } } } question solved, thank you.
well, 'can' add crosshair @ current touch position.
i can tell 1 of many possible ways of doing this.
implement
- (ibaction)handlepan:(uipangesturerecognizer *)recognizer action handler.
load image of crosshair uiimage (say overlayimage):
overlayimage =[uiimage imagenamed:@"crosshair.png"]; and set uiview (say overlayview). [this can done in viewdidload method itself.]
now, add following code handlepan method:
cgpoint translation = [recognizer translationinview:colorview]; //whichever view want. _overlayview.center = cgpointmake(_overlayview.center.x + translation.x, _overlayview.center.y + translation.y); [recognizer settranslation:cgpointmake(0, 0) inview:colorview]; if (recognizer.state == uigesturerecognizerstateended) { cgpoint velocity = [recognizer velocityinview:colorview]; cgfloat magnitude = sqrtf((velocity.x * velocity.x) + (velocity.y * velocity.y)); cgfloat slidemult = magnitude / 800; // nslog(@"magnitude: %f, slidemult: %f", magnitude, slidemult); float slidefactor = 0.1 * slidemult; // increase more of slide cgpoint finalpoint = cgpointmake(_overlayview.center.x + (velocity.x * slidefactor), _overlayview.center.y + (velocity.y * slidefactor)); finalpoint.x = min(max(finalpoint.x, 0), colorview.bounds.size.width); finalpoint.y = min(max(finalpoint.y, 0), colorview.bounds.size.height); [uiview animatewithduration:slidefactor*2 delay:0 options:uiviewanimationoptioncurveeaseout animations:^{ _overlayview.center = finalpoint; } completion:nil]; that should trick.
you may try doing implementing touchesbegan , touchesmoved method.
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