IOS水晶图片制作

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最新推荐文章于 2025-08-12 15:24:57 发布

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分类专栏：程序人生文章标签： ios colors components image null button

本文链接：https://blog.youkuaiyun.com/chenguoshuang/article/details/6700724

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头文件：

#include <CoreGraphics/CoreGraphics.h>

//绘制方式常量
//一个矩形区域
#define FS_DRAW_REGION_RECT (1 << 31)
//左上角圆角
#define FS_DRAW_REGION_LEFT_TOP_RADIUS (1)
//右上角圆角
#define FS_DRAW_REGION_RIGHT_TOP_RADIUS (1 << 1)
//右下角圆角
#define FS_DRAW_REGION_RIGHT_BOTTOM_RADIUS (1 << 2)
//左下角圆角
#define FS_DRAW_REGION_LEFT_BOTTOM_RADIUS (1 << 3)
//四周圆角
#define FS_DRAW_REGION_ROUND_RECT (FS_DRAW_REGION_LEFT_TOP_RADIUS | FS_DRAW_REGION_RIGHT_TOP_RADIUS | FS_DRAW_REGION_RIGHT_BOTTOM_RADIUS | FS_DRAW_REGION_LEFT_BOTTOM_RADIUS)

//从上往下
#define FS_LIGHT_FROM_TOP_TO_BOTTOM (1 << 8)
//从左往右
#define FS_LIGHT_FROM_LEFT_TO_RIGHT (1 << 9)
//从下往上
#define FS_LIGHT_FROM_BOTTOM_TO_TOP (1 << 10)
//从右往左
#define FS_LIGHT_FROM_RIGHT_TO_LEFT (1 << 11)
//从里往外
#define FS_LIGHT_FROM_INNER_TO_OUTER (1 << 12)
//往外往里
#define FS_LIGHT_FROM_OUTER_TO_INNER (1 << 13)

#define FS_ARROW_UP (1)
#define FS_ARROW_DOWN (1 << 1)
#define FS_ARROW_LEFT (1 << 2)
#define FS_ARROW_RIGHT (1 << 3)

//文本位置
#define TEXT_ALIGN_LEFT (1)
#define TEXT_ALIGN_RIGHT (2)
#define TEXT_ALIGN_TOP (3)
#define TEXT_ALIGN_BOTTOM (4)

//矩形渐变方向
#define GRADIENT_RECT_FROM_TOP_TO_BOTTOM (1)
#define GRADIENT_RECT_FROM_BOTTOM_TO_TOP (2)
#define GRADIENT_RECT_FROM_LEFT_TO_RIGHT (3)
#define GRADIENT_RECT_FROM_RIGHT_TO_LEFT (4)

//////////////////////////////////////////////////////////////////
//	函数说明：FOUNDATION_EXTERN
//////////////////////////////////////////////////////////////////

FOUNDATION_EXTERN void buildPathForRect(CGContextRef context, CGRect rect, CGFloat radius, NSUInteger radiusflag);

FOUNDATION_EXTERN void drawLightForPath(CGContextRef context, CGRect rect, NSUInteger lightFlag, CGGradientRef gradient, CGFloat startRadius, CGFloat endRadius);

FOUNDATION_EXTERN void drawCrystalRect(CGContextRef context, CGRect rect, CGFloat radius, const CGFloat *components, NSUInteger componentCount);

FOUNDATION_EXTERN UIImage *createImageWithRect(CGRect rect, CGFloat radius, const CGFloat *components, NSUInteger componentCount);

FOUNDATION_EXTERN void drawNavigatorArrow(CGContextRef context, CGRect rect, NSUInteger arrowDirection, const CGFloat *components, NSUInteger componentCount);

FOUNDATION_EXTERN UIImage *createNavigatorArrowWithRect(CGRect rect, NSUInteger arrowDirection, CGFloat boundSpace, const CGFloat *components, NSUInteger componentCount);

FOUNDATION_EXTERN void drawImageWithRect(CGContextRef context, CGRect rect, UIImage *image);

FOUNDATION_EXTERN UIImage *scaleImage(UIImage *source, CGSize destSize);

FOUNDATION_EXTERN UIImage *drawImageAndTextInRect(CGRect rect, UIImage *source, NSString *text, NSInteger textAlign);

//FOUNDATION_EXTERN void drawButtonImage

//还得加入参数，抽取成为一个函数
FOUNDATION_EXTERN UIImage *createImageInRectWithGradient(CGRect rect, CGFloat radius, const CGFloat *components, NSUInteger componentCount, CGFloat borderWidth);

FOUNDATION_EXTERN void drawGradientInRect(CGRect rect, CGContextRef context, CGColorSpaceRef colorSpace, const CGFloat *components, NSUInteger componentCount, NSUInteger directFlag);

FOUNDATION_EXTERN void drawTopGradientInRect(CGRect rect, CGContextRef context, CGColorSpaceRef colorSpace);
FOUNDATION_EXTERN void drawBottomGradientInRect(CGRect rect, CGContextRef context, CGColorSpaceRef colorSpace);

FOUNDATION_EXTERN void drawGradientInRectWithSingleColor(CGRect rect, CGFloat radius, CGFloat borderWidth, CGContextRef context, CGColorSpaceRef colorSpace, const CGFloat *components, NSUInteger componentCount, NSUInteger directFlag);

.mm 文件

#include "FSGraphicsEx.h"

#define RGB_ADDTION (30.0f / 255.0f)

typedef void(* DRAW_GRADIENT_FUNC)(CGContextRef, CGRect, CGColorSpaceRef, CGFloat *, CGFloat, NSUInteger);

void buildPathForRect(CGContextRef context, CGRect rect, CGFloat radius, NSUInteger radiusflag) {
	if ((radiusflag & FS_DRAW_REGION_RECT) == FS_DRAW_REGION_RECT || radius == 0) {
#ifdef MYDEBUG
		NSLog(@"FS_DRAW_REGION_RECT");
#endif
		CGContextMoveToPoint(context, CGRectGetMinX(rect), CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, CGRectGetMaxX(rect), CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, CGRectGetMaxX(rect), CGRectGetMaxY(rect));
		CGContextAddLineToPoint(context, CGRectGetMinX(rect), CGRectGetMaxY(rect));
		CGContextClosePath(context);
	} else {
		//左上
		CGContextMoveToPoint(context, CGRectGetMinX(rect), CGRectGetMidY(rect));
		if ((radiusflag & FS_DRAW_REGION_LEFT_TOP_RADIUS) == FS_DRAW_REGION_LEFT_TOP_RADIUS) {
#ifdef MYDEBUG
			NSLog(@"FS_DRAW_REGION_LEFT_TOP_RADIUS");
#endif
			CGContextAddArcToPoint(context, CGRectGetMinX(rect), CGRectGetMinY(rect), CGRectGetMidX(rect), CGRectGetMinY(rect), radius);
		} else {
			CGContextAddLineToPoint(context, CGRectGetMinX(rect), CGRectGetMinY(rect));
		}
		CGContextAddLineToPoint(context, CGRectGetMidX(rect), CGRectGetMinY(rect));
		
		//右上
		if ((radiusflag & FS_DRAW_REGION_RIGHT_TOP_RADIUS) == FS_DRAW_REGION_RIGHT_TOP_RADIUS) {
#ifdef MYDEBUG
			NSLog(@"FS_DRAW_REGION_RIGHT_TOP_RADIUS");
#endif
			CGContextAddArcToPoint(context, CGRectGetMaxX(rect), CGRectGetMinY(rect), CGRectGetMaxX(rect), CGRectGetMidY(rect), radius);
		} else {
			CGContextAddLineToPoint(context, CGRectGetMaxX(rect), CGRectGetMinY(rect));
		}
		CGContextAddLineToPoint(context, CGRectGetMaxX(rect), CGRectGetMidY(rect));

		//右下
		if ((radiusflag & FS_DRAW_REGION_RIGHT_BOTTOM_RADIUS) == FS_DRAW_REGION_RIGHT_BOTTOM_RADIUS) {
#ifdef MYDEBUG
			NSLog(@"FS_DRAW_REGION_RIGHT_BOTTOM_RADIUS");
#endif			
			CGContextAddArcToPoint(context, CGRectGetMaxX(rect), CGRectGetMaxY(rect), CGRectGetMidX(rect), CGRectGetMaxY(rect), radius);
		} else {
			CGContextAddLineToPoint(context, CGRectGetMaxX(rect), CGRectGetMaxY(rect));
		}
		CGContextAddLineToPoint(context, CGRectGetMidX(rect), CGRectGetMaxY(rect));
		
		//左下
		if ((radiusflag & FS_DRAW_REGION_LEFT_BOTTOM_RADIUS) == FS_DRAW_REGION_LEFT_BOTTOM_RADIUS) {
#ifdef MYDEBUG
			NSLog(@"FS_DRAW_REGION_LEFT_BOTTOM_RADIUS");
#endif
			CGContextAddArcToPoint(context, CGRectGetMinX(rect), CGRectGetMaxY(rect), CGRectGetMinX(rect), CGRectGetMidY(rect), radius);
		} else {
			CGContextAddLineToPoint(context, CGRectGetMinX(rect), CGRectGetMaxY(rect));
		}
		CGContextAddLineToPoint(context, CGRectGetMinX(rect), CGRectGetMidY(rect));
		
		if (radiusflag == FS_DRAW_REGION_ROUND_RECT) {
			CGContextClosePath(context);
		}
	}
}

void drawLightForPath(CGContextRef context, CGRect rect, NSUInteger lightFlag, CGGradientRef gradient, CGFloat startRadius, CGFloat endRadius) {
	CGPoint startPoint = CGPointZero;
	CGPoint endPoint = CGPointZero;
	if (lightFlag == FS_LIGHT_FROM_INNER_TO_OUTER ||
		lightFlag == FS_LIGHT_FROM_OUTER_TO_INNER) {
		CGFloat radius1 = 0;
		CGFloat radius2 = 0;
		startPoint = CGPointMake(CGRectGetMinX(rect) + rect.size.width / 2.0f, CGRectGetMinY(rect) + rect.size.height / 2.0f);
		endPoint = startPoint;
		if (lightFlag == FS_LIGHT_FROM_INNER_TO_OUTER) {
			radius1 = MIN(startRadius, endRadius);
			radius2 = MAX(startRadius, endRadius);
		} else {
			radius1 = MAX(startRadius, endRadius);
			radius2 = MIN(startRadius, endRadius);
		}
		CGContextDrawRadialGradient(context, gradient, startPoint, radius1, endPoint, radius2, 0);
	} else {

		if (lightFlag == FS_LIGHT_FROM_TOP_TO_BOTTOM) {
			startPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMinY(rect));
			endPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMaxY(rect));
		} else if (lightFlag == FS_LIGHT_FROM_LEFT_TO_RIGHT) {
			startPoint = CGPointMake(CGRectGetMinX(rect), CGRectGetMidY(rect));
			endPoint = CGPointMake(CGRectGetMaxX(rect), CGRectGetMidY(rect));
		} else if (lightFlag == FS_DRAW_REGION_LEFT_BOTTOM_RADIUS) {
			startPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMaxY(rect));
			endPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMinY(rect));
		} else if (lightFlag == FS_LIGHT_FROM_RIGHT_TO_LEFT) {
			startPoint = CGPointMake(CGRectGetMaxX(rect), CGRectGetMidY(rect));
			endPoint = CGPointMake(CGRectGetMinX(rect), CGRectGetMidY(rect));
		} 
		CGContextDrawLinearGradient(context, gradient, startPoint, endPoint, 0);
	}
}

void drawCrystalRect(CGContextRef context, CGRect rect, CGFloat radius, const CGFloat *components, NSUInteger componentCount) {
	//STEP 1.
	CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
	
	//STEP 2.
	CGFloat colors[4] = {0};
	if (componentCount >= 4) {
		colors[0] = components[0];
		colors[1] = components[1];
		colors[2] = components[2];
		colors[3] = components[3];
	} else if (componentCount == 2) {
		colors[0] = components[0];
		colors[1] = components[0];
		colors[2] = components[0];
		colors[3] = components[1];
	}
#ifdef MYDEBUG
	NSLog(@"componentCount=%d;r=%f;g=%f;b=%f;a=%f", componentCount, colors[0], colors[1], colors[2], colors[3]);
#endif
	CGRect rClient = rect;
	rClient.origin.x++;
	rClient.origin.y++;
	rClient.size.width -= 2;
	rClient.size.height -= 2;
	CGContextSaveGState(context);
	buildPathForRect(context, rClient, radius, (FS_DRAW_REGION_LEFT_TOP_RADIUS | FS_DRAW_REGION_RIGHT_TOP_RADIUS | FS_DRAW_REGION_RIGHT_BOTTOM_RADIUS | FS_DRAW_REGION_LEFT_BOTTOM_RADIUS));
	CGContextSetRGBFillColor(context, colors[0], colors[1], colors[2], colors[3]);
	CGContextSetRGBStrokeColor(context, colors[0], colors[1], colors[2], colors[3]);
	CGContextSetLineWidth(context, 2.0f);
	CGContextDrawPath(context, kCGPathFillStroke);
	CGContextRestoreGState(context);
	
	//STEP 3.
	CGContextSaveGState(context);
	CGContextSetLineWidth(context, 2.0f);
	CGFloat topGradientColors[] = 
	{
		1.0f, 1.0f, 1.0f, 0.6,
		1.0f, 1.0f, 1.0f, 0.3,
		1.0f, 1.0f, 1.0f, 0.0
		
	};
	CGRect topRect = CGRectMake(CGRectGetMinX(rClient), CGRectGetMinY(rClient), rClient.size.width, rClient.size.height / 2.0f);
	CGGradientRef topGradient = CGGradientCreateWithColorComponents(colorSpace, topGradientColors, NULL, sizeof(topGradientColors) / (4 * sizeof(CGFloat)));
	buildPathForRect(context, topRect, radius, (FS_DRAW_REGION_LEFT_TOP_RADIUS | FS_DRAW_REGION_RIGHT_TOP_RADIUS));
	CGContextClip(context);
	drawLightForPath(context, topRect, FS_LIGHT_FROM_TOP_TO_BOTTOM, topGradient, 0.0f, 0.0f);
	CGGradientRelease(topGradient);
	CGContextRestoreGState(context);
	
	//STEP 4.
	CGContextSaveGState(context);
	CGContextSetLineWidth(context, 2.0f);
	CGFloat bottomGradientColors[] = 
	{
		0.0f, 0.0f, 0.0f, 0.15,
		0.0f, 0.0f, 0.0f, 0.15,
		0.0f, 0.0f, 0.0f, 0.15
	};
	CGRect bottomRect = CGRectMake(CGRectGetMinX(rClient), CGRectGetMidY(rClient), rClient.size.width, rClient.size.height / 2.0f);
	CGGradientRef bottomGradient = CGGradientCreateWithColorComponents(colorSpace, bottomGradientColors, NULL, sizeof(bottomGradientColors) / (4 * sizeof(CGFloat)));
	buildPathForRect(context, bottomRect, radius, FS_DRAW_REGION_RIGHT_BOTTOM_RADIUS | FS_DRAW_REGION_LEFT_BOTTOM_RADIUS);
	CGContextClip(context);
	drawLightForPath(context, bottomRect, FS_LIGHT_FROM_TOP_TO_BOTTOM, bottomGradient, 0.0f, 0.0f);
	CGGradientRelease(bottomGradient);
	CGContextRestoreGState(context);
	
	//STEP 5.
	rect.origin.x += 0.5;
	rect.origin.y += 0.5;
	rect.size.width -= 1;
	rect.size.height -= 1;
	CGContextSaveGState(context);
	buildPathForRect(context, rect, radius, (FS_DRAW_REGION_LEFT_TOP_RADIUS | FS_DRAW_REGION_RIGHT_TOP_RADIUS | FS_DRAW_REGION_RIGHT_BOTTOM_RADIUS | FS_DRAW_REGION_LEFT_BOTTOM_RADIUS));
	colors[0] += RGB_ADDTION * 1.2;
	colors[1] += RGB_ADDTION * 1.2;
	colors[2] += RGB_ADDTION * 1.2;
	if (colors[0] > 1) {
		colors[0] = 1.0f;
	}
	if (colors[1] > 1) {
		colors[1] = 1.0f;
	}
	if (colors[2] > 1) {
		colors[2] = 1.0f;
	}
	
	//CGContextSetRGBStrokeColor(context, 125.0f / 255.0f, 125.0f / 255.0f, 125.0f / 255.0f, 1.0f);
	CGContextSetRGBStrokeColor(context, colors[0], colors[1], colors[2], 1.0f);
	CGContextSetLineWidth(context, 1);
	CGContextDrawPath(context, kCGPathStroke);
	CGContextRestoreGState(context);
	
	//STEP 6.
	CGContextSaveGState(context);
	rect.origin.x += 1;
	rect.origin.y += 1;
	rect.size.width -= 2;
	rect.size.height -= 2;
	radius--;
	colors[0] -= RGB_ADDTION * 1.5f;
	colors[1] -= RGB_ADDTION * 1.5f;
	colors[2] -= RGB_ADDTION * 1.5f;
	if (colors[0] < 0) {
		colors[0] = 0.0f;
	}
	if (colors[1] < 0) {
		colors[1] = 0.0f;
	}
	if (colors[2] < 0) {
		colors[2] = 0.0f;
	}
	buildPathForRect(context, rect, radius, (FS_DRAW_REGION_LEFT_TOP_RADIUS | FS_DRAW_REGION_RIGHT_TOP_RADIUS | FS_DRAW_REGION_RIGHT_BOTTOM_RADIUS | FS_DRAW_REGION_LEFT_BOTTOM_RADIUS));
	//CGContextSetRGBStrokeColor(context, 229.0f / 255.0f, 229.0f / 255.0f, 229.0f / 255.0f, 1.0f);
	CGContextSetRGBStrokeColor(context, colors[0], colors[1], colors[2], 1.0f);
	CGContextSetLineWidth(context, 1.5);
	CGContextDrawPath(context, kCGPathStroke);
	CGContextRestoreGState(context);
	
	//STEP 7.
	CGColorSpaceRelease(colorSpace);
	
}

UIImage *createImageWithRect(CGRect rect, CGFloat radius, const CGFloat *components, NSUInteger componentCount) {
	UIImage *result = nil;
	//STEP 1.
	CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
	CGContextRef context = CGBitmapContextCreate(NULL, rect.size.width, rect.size.height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Little);
	CGContextTranslateCTM (context, 0, rect.size.height);
	CGContextScaleCTM(context, 1.0, -1.0);
	
	//STEP 2.
	drawCrystalRect(context, CGRectMake(0.0f, 0.0f, rect.size.width, rect.size.height), radius, components, componentCount);
	
	//STEP 3.
	CGImageRef image = CGBitmapContextCreateImage(context);
	result = [UIImage imageWithCGImage:image];
	CGImageRelease(image);
	
	CGContextRelease(context);
	CGColorSpaceRelease(colorSpace);
	
	//STEP 4.
	return result;
}

/////////////////////////////////////////
//	绘制导航箭头
////////////////////////////////////////
void drawNavigatorArrow(CGContextRef context, CGRect rect, NSUInteger arrowDirection, const CGFloat *components, NSUInteger componentCount) {
	CGFloat colors[4] = {0};
	if (componentCount >= 4) {
		colors[0] = components[0];
		colors[1] = components[1];
		colors[2] = components[2];
		colors[3] = components[3];
	} else if (componentCount == 2) {
		colors[0] = components[0];
		colors[1] = components[0];
		colors[2] = components[0];
		colors[3] = components[1];
	} else {
		colors[0] = 239.0f / 255.0f;
		colors[1] = 239.0f / 255.0f;
		colors[2] = 239.0f / 255.0f;
		colors[3] = 1.0f;
	}

	
	//STEP 1.
	CGContextSaveGState(context);
	CGContextSetRGBStrokeColor(context, 1.0f, 1.0f, 1.0f, 0.0f);
	CGContextSetRGBFillColor(context, 1.0f, 1.0f, 1.0f, 0.0f);
	CGContextSetLineWidth(context, 0.0f);
	buildPathForRect(context, rect, 0.0f, FS_DRAW_REGION_RECT);
	CGContextDrawPath(context, kCGPathFillStroke);
	CGContextRestoreGState(context);
	
	//STEP 2.
	CGContextSaveGState(context);
	if (arrowDirection == FS_ARROW_UP) {
		CGContextMoveToPoint(context, CGRectGetMidX(rect), CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, CGRectGetMaxX(rect), CGRectGetMidY(rect));
		CGContextAddLineToPoint(context, rect.size.width * 2 / 3.0f + CGRectGetMinX(rect), CGRectGetMidY(rect));
		CGContextAddLineToPoint(context, rect.size.width * 2 / 3.0f + CGRectGetMinX(rect), CGRectGetMaxY(rect));
		CGContextAddLineToPoint(context, rect.size.width / 3.0f + CGRectGetMinX(rect), CGRectGetMaxY(rect));
		CGContextAddLineToPoint(context, rect.size.width / 3.0f + CGRectGetMinX(rect), CGRectGetMidY(rect));
		CGContextAddLineToPoint(context, CGRectGetMinX(rect), CGRectGetMidY(rect));
		CGContextClosePath(context);
	} else if (arrowDirection == FS_ARROW_DOWN) {
		CGContextMoveToPoint(context, CGRectGetMidX(rect), CGRectGetMaxY(rect));
		CGContextAddLineToPoint(context, CGRectGetMaxX(rect), CGRectGetMidY(rect));
		CGContextAddLineToPoint(context, rect.size.width * 2 / 3.0f + CGRectGetMinX(rect), CGRectGetMidY(rect));
		CGContextAddLineToPoint(context, rect.size.width * 2 / 3.0f + CGRectGetMinX(rect), CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, rect.size.width / 3.0f + CGRectGetMinX(rect), CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, rect.size.width / 3.0f + CGRectGetMinX(rect), CGRectGetMidY(rect));
		CGContextAddLineToPoint(context, CGRectGetMinX(rect), CGRectGetMidY(rect));
		CGContextClosePath(context);
	} else if (arrowDirection == FS_ARROW_LEFT) {
		CGContextMoveToPoint(context, CGRectGetMinX(rect), CGRectGetMidY(rect));
		CGContextAddLineToPoint(context, CGRectGetMidX(rect), CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, CGRectGetMidX(rect), rect.size.height / 3.0f + CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, CGRectGetMaxX(rect), rect.size.height / 3.0f + CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, CGRectGetMaxX(rect), rect.size.height * 2.0 / 3.0f + CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, CGRectGetMidX(rect), rect.size.height * 2.0 / 3.0f + CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, CGRectGetMidX(rect), CGRectGetMaxY(rect));
		CGContextClosePath(context);
	} else if (arrowDirection == FS_ARROW_RIGHT) {
		CGContextMoveToPoint(context, CGRectGetMaxX(rect), CGRectGetMidY(rect));
		CGContextAddLineToPoint(context, CGRectGetMidX(rect), CGRectGetMaxY(rect));
		CGContextAddLineToPoint(context, CGRectGetMidX(rect), rect.size.height * 2.0 / 3.0f + CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, CGRectGetMinX(rect), rect.size.height * 2.0 / 3.0f + CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, CGRectGetMinX(rect), rect.size.height / 3.0f + CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, CGRectGetMidX(rect), rect.size.height / 3.0f + CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, CGRectGetMidX(rect), CGRectGetMinY(rect));
		CGContextClosePath(context);
	} else {
		CGContextMoveToPoint(context, CGRectGetMinX(rect), CGRectGetMidY(rect));
		CGContextAddLineToPoint(context, CGRectGetMidX(rect), CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, CGRectGetMidX(rect), rect.size.height / 3.0f + CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, CGRectGetMaxX(rect), rect.size.height / 3.0f + CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, CGRectGetMaxX(rect), rect.size.height * 2.0 / 3.0f + CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, CGRectGetMidX(rect), rect.size.height * 2.0 / 3.0f + CGRectGetMinY(rect));
		CGContextAddLineToPoint(context, CGRectGetMidX(rect), CGRectGetMaxY(rect));
		CGContextClosePath(context);
	}
	CGContextSetRGBFillColor(context, colors[0], colors[1], colors[2], colors[3]);
	CGContextSetRGBStrokeColor(context, colors[0], colors[1], colors[2], colors[3]);
	CGContextSetLineWidth(context, 1.0f);
	CGContextDrawPath(context, kCGPathFillStroke);
	CGContextRestoreGState(context);
}

UIImage *createNavigatorArrowWithRect(CGRect rect, NSUInteger arrowDirection, CGFloat boundSpace, const CGFloat *components, NSUInteger componentCount) {
	UIImage *result = nil;
	//STEP 1.
	CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
	CGContextRef context = CGBitmapContextCreate(NULL, rect.size.width, rect.size.height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Little);
	CGContextTranslateCTM (context, 0, rect.size.height);
	CGContextScaleCTM(context, 1.0, -1.0);
	
	//STEP 2.
	CGRect rArrow = CGRectMake(boundSpace + CGRectGetMinX(rect), boundSpace + CGRectGetMinY(rect), rect.size.width - boundSpace * 2.0f, rect.size.height - boundSpace * 2.0f);
	drawNavigatorArrow(context, rArrow, arrowDirection, components, componentCount);
	
	//STEP 3.
	CGImageRef image = CGBitmapContextCreateImage(context);
	result = [UIImage imageWithCGImage:image];
	CGImageRelease(image);
	
	CGContextRelease(context);
	CGColorSpaceRelease(colorSpace);
	
	//STEP 4.
	return result;
}

UIImage *scaleImage(UIImage *source, CGSize destSize) {
	CGFloat destW = destSize.width;
	CGFloat destH = destSize.height;
	
	CGImageRef imageRef = source.CGImage;
	
	CGBitmapInfo bitmapInfo = kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedLast;//CGImageGetBitmapInfo(imageRef);
	CGColorSpaceRef colorSpaceInfo = CGImageGetColorSpace(imageRef);
	
	CGContextRef bitmap = NULL;
	
	size_t bitsPerComponent = CGImageGetBitsPerComponent(imageRef);
	size_t bytesPerRow = 0;// CGImageGetBytesPerRow(imageRef);
#ifdef MYDEBUG
	NSLog(@"bitsPerComponent=%d;bytesPerRow=%d", bitsPerComponent, bytesPerRow);
#endif
	
	if (source.imageOrientation == UIImageOrientationUp || source.imageOrientation == UIImageOrientationDown) {
		bitmap = CGBitmapContextCreate(NULL, destW, destH, bitsPerComponent, bytesPerRow, colorSpaceInfo, bitmapInfo);
	} else {
		bitmap = CGBitmapContextCreate(NULL, destH, destW, bitsPerComponent, bytesPerRow, colorSpaceInfo, bitmapInfo);
	}
	
	if (source.imageOrientation == UIImageOrientationLeft) {
		CGContextRotateCTM (bitmap, M_PI / 2.0f);
		CGContextTranslateCTM (bitmap, 0, - destW);
	} else if (source.imageOrientation == UIImageOrientationRight) {
		CGContextRotateCTM (bitmap, - M_PI / 2.0f);
		CGContextTranslateCTM (bitmap, - destW, 0);
	} else if (source.imageOrientation == UIImageOrientationUp) {
		// NOTHING
	} else if (source.imageOrientation == UIImageOrientationDown) {
		CGContextTranslateCTM (bitmap, destW, destH);
		CGContextRotateCTM (bitmap, - M_PI);
	}
	
	//CGContextScaleCTM(bitmap, destW / source.size.width, destH / source.size.height);
	CGContextDrawImage(bitmap, CGRectMake(0, 0, destW, destH), imageRef);
	
	CGImageRef ref = CGBitmapContextCreateImage(bitmap);
	UIImage *result = [UIImage imageWithCGImage:ref];
	CGContextRelease(bitmap);
	CGImageRelease(ref);
	
	return result;
}

void drawImageWithRect(CGContextRef context, CGRect rect, UIImage *image) {
	NSInteger colCount = rect.size.width / image.size.width + 1;
	NSInteger rowCount = rect.size.height / image.size.height + 1;
	
	CGFloat left = CGRectGetMinX(rect);
	CGFloat top = CGRectGetMinY(rect);
	for (int i = 0; i < rowCount; i++) {
		for (int j = 0; j < colCount; j++) {
			CGRect rImage = CGRectMake(left, top, image.size.width, image.size.height);
			CGContextDrawImage(context, rImage, image.CGImage);
			left += rImage.size.width;
		}
		top += image.size.height;
		left = CGRectGetMinX(rect);
		//top += 100;
	}
}


UIImage *drawImageAndTextInRect(CGRect rect, UIImage *source, NSString *text, NSInteger textAlign) {
	UIImage *result = nil;
	CGFloat radius = 4.0f;
	CGFloat components[] = 
	{
		184.0f / 255.0f,
		235.0f / 255.0f,
		255.0f / 255.0f,
		1.0f
	};
	
	NSInteger componentCount = sizeof(components) / sizeof(CGFloat);
	
	//STEP 1.
	CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
	CGContextRef context = CGBitmapContextCreate(NULL, rect.size.width, rect.size.height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Little);
	CGContextTranslateCTM (context, 0, rect.size.height);
	CGContextScaleCTM(context, 1.0, -1.0);
	
	//STEP 2.
	drawCrystalRect(context, CGRectMake(0.0f, 0.0f, rect.size.width, rect.size.height), radius, components, componentCount);
	
	//STEP 3.文字
	
	
	//STEP 3.
	CGImageRef image = CGBitmapContextCreateImage(context);
	result = [UIImage imageWithCGImage:image];
	CGImageRelease(image);
	
	CGContextRelease(context);
	CGColorSpaceRelease(colorSpace);
	
	//STEP 4.
	return result;
}

UIImage *createImageInRectWithGradient(CGRect rect, CGFloat radius, const CGFloat *components, NSUInteger componentCount, CGFloat borderWidth) {
	UIImage *result = nil;
	//STEP 1.
	CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
	CGContextRef context = CGBitmapContextCreate(NULL, rect.size.width, rect.size.height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Little);
	CGContextTranslateCTM (context, 0, rect.size.height);
	CGContextScaleCTM(context, 1.0, -1.0);
	
	//STEP 2.
	drawGradientInRectWithSingleColor(rect, radius, borderWidth, context, colorSpace, components, componentCount, GRADIENT_RECT_FROM_TOP_TO_BOTTOM);

	//STEP 3.
	CGImageRef image = CGBitmapContextCreateImage(context);
	result = [UIImage imageWithCGImage:image];
	CGImageRelease(image);
	
	CGContextRelease(context);
	CGColorSpaceRelease(colorSpace);
	
	//STEP 4.
	return result;
}

//在一个矩形内部进行绘制渐变
void drawGradientInRect(CGRect rect, CGContextRef context, CGColorSpaceRef colorSpace, const CGFloat *components, NSUInteger componentCount, NSUInteger directFlag) {
	CGGradientRef gradient = CGGradientCreateWithColorComponents(colorSpace, components, NULL, componentCount / 4);
	CGPoint startPoint = CGPointZero;
	CGPoint endPoint = CGPointZero;
	if (directFlag == GRADIENT_RECT_FROM_TOP_TO_BOTTOM) {
		startPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMinY(rect));
		endPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMaxY(rect));
	} else if (directFlag == GRADIENT_RECT_FROM_BOTTOM_TO_TOP) {
		endPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMinY(rect));
		startPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMaxY(rect));
	} else if (directFlag == GRADIENT_RECT_FROM_LEFT_TO_RIGHT) {
		startPoint = CGPointMake(CGRectGetMinX(rect), CGRectGetMidY(rect));
		endPoint = CGPointMake(CGRectGetMaxX(rect), CGRectGetMidY(rect));
	} else if (directFlag == GRADIENT_RECT_FROM_RIGHT_TO_LEFT) {
		endPoint = CGPointMake(CGRectGetMinX(rect), CGRectGetMidY(rect));
		startPoint = CGPointMake(CGRectGetMaxX(rect), CGRectGetMidY(rect));
	} else {
		startPoint = CGPointMake(CGRectGetMinX(rect), CGRectGetMidY(rect));
		endPoint = CGPointMake(CGRectGetMaxX(rect), CGRectGetMidY(rect));
	}

	CGContextDrawLinearGradient(context, 
								gradient, 
								startPoint, 
								endPoint, 
								0);
	CGGradientRelease(gradient);
}

void drawTopGradientInRect(CGRect rect, CGContextRef context, CGColorSpaceRef colorSpace) {
	CGFloat colorTop[] =
	{
		//239.0f / 255.0f, 239.0f / 255.0f, 239.0f / 255.0f, 0.35f,
		239.0f / 255.0f, 239.0f / 255.0f, 239.0f / 255.0f, 0.40f,
		//239.0f / 255.0f, 239.0f / 255.0f, 239.0f / 255.0f, 0.25f,
		239.0f / 255.0f, 239.0f / 255.0f, 239.0f / 255.0f, 0.20f,
		//239.0f / 255.0f, 239.0f / 255.0f, 239.0f / 255.0f, 0.15f,
		239.0f / 255.0f, 239.0f / 255.0f, 239.0f / 255.0f, 0.10f,
		239.0f / 255.0f, 239.0f / 255.0f, 239.0f / 255.0f, 0.05f,
		239.0f / 255.0f, 239.0f / 255.0f, 239.0f / 255.0f, 0.0f,
		
	};
	drawGradientInRect(rect, context, colorSpace, colorTop, sizeof(colorTop) / sizeof(CGFloat), GRADIENT_RECT_FROM_TOP_TO_BOTTOM);
}

void drawBottomGradientInRect(CGRect rect, CGContextRef context, CGColorSpaceRef colorSpace) {
	CGFloat colorBottom[] = 
	{
		//5.0f / 255.0f, 5.0f / 255.0f, 5.0f / 255.0f, 0.05f,
		//5.0f / 255.0f, 5.0f / 255.0f, 5.0f / 255.0f, 0.20f,
		5.0f / 255.0f, 5.0f / 255.0f, 5.0f / 255.0f, 0.15f,
		5.0f / 255.0f, 5.0f / 255.0f, 5.0f / 255.0f, 0.25f,
		5.0f / 255.0f, 5.0f / 255.0f, 5.0f / 255.0f, 0.35f,
		5.0f / 255.0f, 5.0f / 255.0f, 5.0f / 255.0f, 0.45f,
		//5.0f / 255.0f, 5.0f / 255.0f, 5.0f / 255.0f, 0.0f,
		
	};
	drawGradientInRect(rect, context, colorSpace, colorBottom, sizeof(colorBottom) / sizeof(CGFloat), GRADIENT_RECT_FROM_TOP_TO_BOTTOM);
}



void drawGradientInRectWithSingleColor(CGRect rect, CGFloat radius, CGFloat borderWidth, CGContextRef context, CGColorSpaceRef colorSpace, const CGFloat *components, NSUInteger componentCount, NSUInteger directFlag) {
	CGFloat borderWidth_Real = borderWidth;
	if (borderWidth_Real >= 0.0f) {
		borderWidth_Real = 1.0f;
	}
	CGFloat colors[4] = {0};
	if (componentCount >= 4) {
		colors[0] = components[0];
		colors[1] = components[1];
		colors[2] = components[2];
		colors[3] = components[3];
	} else if (componentCount == 2) {
		colors[0] = components[0];
		colors[1] = components[0];
		colors[2] = components[0];
		colors[3] = components[1];
	}
	
	CGRect rClient = rect;
	CGFloat boundsSpace = 1.0f;
	rClient.origin.x += (borderWidth_Real / 2.0f + boundsSpace);
	rClient.origin.y += (borderWidth_Real / 2.0f + boundsSpace); 
	rClient.size.width -= (borderWidth_Real + boundsSpace * 2.0f);
	rClient.size.height -= (borderWidth_Real + boundsSpace * 2.0f);
	
	//STEP 1.
	CGContextSaveGState(context);
	CGContextSetRGBFillColor(context, colors[0], colors[1], colors[2], colors[3]);
	CGContextSetRGBStrokeColor(context, colors[0], colors[1], colors[3], colors[3]);
	buildPathForRect(context, rClient, radius, FS_DRAW_REGION_ROUND_RECT);
	UIColor *shadowColor = [[UIColor alloc] initWithRed:colors[0] green:colors[1] blue:colors[2] alpha:colors[3]];
	CGContextSetShadowWithColor(context, CGSizeMake(-1.0f, 1.0f), 2.0f, shadowColor.CGColor);
	[shadowColor release];
	CGContextSetLineWidth(context, 0.0f);
	CGContextDrawPath(context, kCGPathFillStroke);
	CGContextRestoreGState(context);
	
	//STEP 2.
	CGContextSaveGState(context);
	CGFloat gradientColors[] = 
	{
		1.0f, 1.0f, 1.0f, 0.75f,
		1.0f, 1.0f, 1.0f, 0.55f,
		1.0f, 1.0f, 1.0f, 0.25f,
		1.0f, 1.0f, 1.0f, 0.0f,
	};
	CGGradientRef gradient = CGGradientCreateWithColorComponents(colorSpace, gradientColors, NULL, sizeof(gradientColors)/ (4 * sizeof(CGFloat)));
	buildPathForRect(context, rClient, radius, FS_DRAW_REGION_ROUND_RECT);
	CGContextClip(context);
	CGPoint startPoint = CGPointZero;
	CGPoint endPoint = CGPointZero;
	if (directFlag == GRADIENT_RECT_FROM_TOP_TO_BOTTOM) {
		startPoint = CGPointMake(CGRectGetMidX(rClient), CGRectGetMinY(rClient));
		endPoint = CGPointMake(CGRectGetMidX(rClient), CGRectGetMaxY(rClient));
	} else if (directFlag == GRADIENT_RECT_FROM_BOTTOM_TO_TOP) {
		endPoint = CGPointMake(CGRectGetMidX(rClient), CGRectGetMinY(rClient));
		startPoint = CGPointMake(CGRectGetMidX(rClient), CGRectGetMaxY(rClient));
	} else if (directFlag == GRADIENT_RECT_FROM_LEFT_TO_RIGHT) {
		startPoint = CGPointMake(CGRectGetMinX(rClient), CGRectGetMidY(rClient));
		endPoint = CGPointMake(CGRectGetMaxX(rClient), CGRectGetMidY(rClient));
	} else if (directFlag == GRADIENT_RECT_FROM_RIGHT_TO_LEFT) {
		endPoint = CGPointMake(CGRectGetMinX(rClient), CGRectGetMidY(rClient));
		startPoint = CGPointMake(CGRectGetMaxX(rClient), CGRectGetMidY(rClient));
	} else {
		startPoint = CGPointMake(CGRectGetMinX(rClient), CGRectGetMidY(rClient));
		endPoint = CGPointMake(CGRectGetMaxX(rClient), CGRectGetMidY(rClient));
	}
	CGContextDrawLinearGradient(context, 
								gradient, 
								startPoint, 
								endPoint, 
								0);
	CGGradientRelease(gradient);
	CGContextRestoreGState(context);
}

使用方法：

	UIColor *btnBGColor = [[UIColor alloc] initWithRed:0.0f / 255.0f green:132.0f / 255.0f blue:189.0f / 255.0f alpha:1.0f];
	UIImage *bgImage = createImageWithRect(CGRectMake(0.0f, 0.0f, SNSLOGIN_BUTTON_WIDTH, SNSLOGIN_BUTTON_HEIGHT), SNSLOGIN_BUTTON_RADIUS, CGColorGetComponents(btnBGColor.CGColor), CGColorGetNumberOfComponents(btnBGColor.CGColor));
	[btnBGColor release];
		
	_btnLogin = [[UIButton alloc] initWithFrame:CGRectZero];
	[_btnLogin setTitle:@"登录" forState:UIControlStateNormal];
	[_btnLogin setBackgroundImage:bgImage forState:UIControlStateNormal];
	[_btnLogin.titleLabel setFont:[UIFont boldSystemFontOfSize:18.0f]];
	[_btnLogin addTarget:self action:@selector(loginAction:) forControlEvents:UIControlEventTouchUpInside];
	[self addSubview:_btnLogin];

示例图片：