我有一个TabBar，我可以选择我想要使用的过滤器。如果我选择一个Slider，我可以使用过滤器。但如果我选择其他滤镜，图像将重置为原始。我怎么能在xcode 5中说所有过滤器都应该保留？
抱歉我的英语不好。我来自德国。
我的过滤器代码：
int b, i;
// Select first tab by default
tabBar.selectedItem = [tabBar.items objectAtIndex:0];
// Create a bitmap context for rendering the tabBar buttons
// Usually, button images are loaded from disk, but these simple shapes can be procedurally generated.
// UITabBar only needs the alpha channel of these images.
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(nil, 30, 30, 6, 0, colorSpace, kCGImageAlphaPremultipliedFirst);
CGImageRef theCGImage;
// Draw with white round strokes
CGContextSetLineCap(context, kCGLineCapRound);
CGContextSetRGBStrokeColor(context, 1.0, 1.0, 1.0, 1.0);
CGContextSetRGBFillColor(context, 1.0, 1.0, 1.0, 1.0);
CGContextSetLineWidth(context, 2.0);
for (b = 0; b < NUM_BUTTONS; b++)
{
CGContextClearRect(context, CGRectMake(0, 0, 30, 30));
switch(b)
{
case BUTTON_BRIGHTNESS:
{
const CGFloat line[8*4] = {
15.0, 6.0, 15.0, 4.0,
15.0,24.0, 15.0,26.0,
6.0,15.0, 4.0,15.0,
24.0,15.0, 26.0,15.0,
21.5,21.5, 23.0,23.0,
8.5, 8.5, 7.0, 7.0,
21.5, 8.5, 23.0, 7.0,
8.5,21.5, 7.0,23.0,
};
// A circle with eight rays around it
CGContextStrokeEllipseInRect(context, CGRectMake(10.5, 10.5, 9.0, 9.0));
for (i = 0; i < 8; i++)
{
CGContextMoveToPoint(context, line[i*4+0], line[i*4+1]);
CGContextAddLineToPoint(context, line[i*4+2], line[i*4+3]);
CGContextStrokePath(context);
}
break;
[BUTTON_BRIGHTNESS setValue: forKey:@"inputImage"];
}
case BUTTON_CONTRAST:
{
// A circle with the right half filled
CGContextStrokeEllipseInRect(context, CGRectMake(4.0, 4.0, 22.0, 22.0));
CGContextAddArc(context, 15.0, 15.0, 11.0, -M_PI/2.0, M_PI/2.0, false);
CGContextFillPath(context);
break;
}
case BUTTON_SATURATION:
{
CGGradientRef gradient;
const CGFloat stripe[3][12] = {
{ 0.3,0.3,0.3,0.15, 1.0,0.0,0.0,0.70, 5, 5, 7, 25 },
{ 0.5,0.5,0.5,0.25, 0.0,1.0,0.0,0.75, 12, 5, 6, 25 },
{ 0.2,0.2,0.2,0.10, 0.0,0.0,1.0,0.65, 18, 5, 7, 25 },
};
// Red/Green/Blue gradients, inside a rounded rect
for (i = 0; i < 3; i++)
{
gradient = CGGradientCreateWithColorComponents(colorSpace, stripe[i], NULL, 2);
CGContextSaveGState(context);
CGContextClipToRect(context, CGRectMake(stripe[i][8], stripe[i][9], stripe[i][10], stripe[i][11]));
CGContextDrawLinearGradient(context, gradient, CGPointMake(15, 5), CGPointMake(15, 25), 0);
CGContextRestoreGState(context);
CGGradientRelease(gradient);
}
CGContextMoveToPoint(context, 4, 15);
CGContextAddArcToPoint(context, 4, 4, 15, 4, 4);
CGContextAddArcToPoint(context, 26, 4, 26, 15, 4);
CGContextAddArcToPoint(context, 26, 26, 15, 26, 4);
CGContextAddArcToPoint(context, 4, 26, 4, 15, 4);
CGContextClosePath(context);
CGContextStrokePath(context);
break;
}
case BUTTON_HUE:
{
CGGradientRef gradient;
CGFloat hue[8];
const int angle = 4;
// A radial gradient, inside a circle
for (i = 0; i < 360; i+=angle)
{
float x = cosf((i+angle*0.5)*DEG2RAD)*10+15;
float y = sinf((i+angle*0.5)*DEG2RAD)*10+15;
float r = (i )/180.0; if (r > 1.0) r = 2.0-r;
float g = (i+120)/180.0; if (g > 2.0) g = g-2.0; else if (g > 1.0) g = 2.0-g;
float b = (i+240)/180.0; if (b > 3.0) b = 4.0-b; else if (b > 2.0) b = b-2.0; else b = 2.0-b;
float a = (i+ 90)/180.0; if (a > 2.0) a = a-2.0; else if (a > 1.0) a = 2.0-a;
hue[0] = hue[4] = r;
hue[1] = hue[5] = g;
hue[2] = hue[6] = b;
hue[3] = a*0.5;
hue[7] = a*0.75;
gradient = CGGradientCreateWithColorComponents(colorSpace, hue, NULL, 2);
CGContextSaveGState(context);
CGContextMoveToPoint(context, 15, 15);
CGContextAddArc(context, 15, 15, 10, i*DEG2RAD, (i+angle)*DEG2RAD, false);
CGContextClosePath(context);
CGContextClip(context);
CGContextDrawLinearGradient(context, gradient, CGPointMake(x, y), CGPointMake(15, 15), 0);
CGContextRestoreGState(context);
CGGradientRelease(gradient);
}
CGContextStrokeEllipseInRect(context, CGRectMake(4.0, 4.0, 22.0, 22.0));
break;
}
case BUTTON_SHARPNESS:
{
int x, y;
// A gradient checkerboard, inside a rounded rect
for (x = 5; x < 25; x+=2)
{
float b = (x - 5)/19.0*0.5+0.375;
if (b > 0.75) b = 0.75;
else if (b < 0.5) b = 0.5;
for (y = 5; y < 25; y+=2)
{
float k = ((x ^ y) & 2) ? b : 1.0-b;
CGContextSetRGBFillColor(context, k, k, k, k);
CGContextFillRect(context, CGRectMake(x, y, 2, 2));
}
}
CGContextSetRGBFillColor(context, 1.0, 1.0, 1.0, 1.0);
CGContextMoveToPoint(context, 4, 15);
CGContextAddArcToPoint(context, 4, 4, 15, 4, 4);
CGContextAddArcToPoint(context, 26, 4, 26, 15, 4);
CGContextAddArcToPoint(context, 26, 26, 15, 26, 4);
CGContextAddArcToPoint(context, 4, 26, 4, 15, 4);
CGContextClosePath(context);
CGContextStrokePath(context);
break;
}
}
theCGImage = CGBitmapContextCreateImage(context);
((UITabBarItem *)[tabBar.items objectAtIndex:b]).image = [UIImage imageWithCGImage:theCGImage];
CGImageRelease(theCGImage);
}
CGContextRelease(context);
CGColorSpaceRelease(colorSpace);
}
答案 0 :(得分：-3)
使用GPUImage过滤器更容易。尝试设置这些，而不是创建另一个问题。