iOS 手写签名的简单实用封装

简介

现在很多项目在完善信息或者注册信息的时候,或者支付这一方面,都希望用户手写签名,这样既可以保证是用户亲自签名的,保证该记录是用用户操作的,而不是别人操作的.所以手写签字这个还是比较重要的.下面就是通过QuartzCore来绘制签名.QuartzCore是iOS的核心动画框架.

绘制

• 1定义一个结构体

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static CGPoint midpoint(CGPoint p0,CGPoint p1) {     return (CGPoint) {         (p0.x + p1.x) /2.0,         (p0.y + p1.y) /2.0     }; }

• 2添加手势

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UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)];     pan.maximumNumberOfTouches = pan.minimumNumberOfTouches =1;     [self addGestureRecognizer:pan];

• 3开始绘制

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CGPoint currentPoint = [pan locationInView:self];     CGPoint midPoint = midpoint(previousPoint, currentPoint);     NSLog(@"获取到的触摸点的位置为--currentPoint:%@",NSStringFromCGPoint(currentPoint));     [self.currentPointArr addObject:[NSValue valueWithCGPoint:currentPoint]];     self.hasSignatureImg = YES;     CGFloat viewHeight = self.frame.size.height;     CGFloat currentY = currentPoint.y;     if (pan.state ==UIGestureRecognizerStateBegan) {         [path moveToPoint:currentPoint];               } else if (pan.state ==UIGestureRecognizerStateChanged) {         [path addQuadCurveToPoint:midPoint controlPoint:previousPoint];                         }           if(0 <= currentY && currentY <= viewHeight)     {         if(max == 0&&min == 0)         {             max = currentPoint.x;             min = currentPoint.x;         }         else         {             if(max <= currentPoint.x)             {                 max = currentPoint.x;             }             if(min>=currentPoint.x)             {                 min = currentPoint.x;             }         }               }           previousPoint = currentPoint;     //记得调用,及时刷新视图     [self setNeedsDisplay];

• 4获取绘制视图,在进行一系列处理就好

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if(UIGraphicsBeginImageContextWithOptions !=NULL)     {         UIGraphicsBeginImageContextWithOptions(self.bounds.size,NO, [UIScreen mainScreen].scale);     }else {         UIGraphicsBeginImageContext(self.bounds.size);               }           [self.layer renderInContext:UIGraphicsGetCurrentContext()];           UIImage *image =UIGraphicsGetImageFromCurrentImageContext();           UIGraphicsEndImageContext();     //绘制成图     image = [self imageBlackToTransparent:image];     NSLog(@"width:%f,height:%f",image.size.width,image.size.height);     //截取图片     UIImage *img = [self cutImage:image];     //压缩图片     self.SignatureImg = [self scaleToSize:img];

• 5附上处理的方法

1.绘制成图

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- (UIImage*) imageBlackToTransparent:(UIImage*) image {     // 分配内存     const int imageWidth = image.size.width;     const int imageHeight = image.size.height;     size_t      bytesPerRow = imageWidth * 4;     uint32_t* rgbImageBuf = (uint32_t*)malloc(bytesPerRow * imageHeight);           // 创建context     CGColorSpaceRef colorSpace =CGColorSpaceCreateDeviceRGB();     CGContextRef context = CGBitmapContextCreate(rgbImageBuf, imageWidth, imageHeight, 8, bytesPerRow, colorSpace,                                                  kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast);           CGContextDrawImage(context, CGRectMake(0, 0, imageWidth, imageHeight), image.CGImage);           // 遍历像素     int pixelNum = imageWidth * imageHeight;     uint32_t* pCurPtr = rgbImageBuf;     for (int i =0; i < pixelNum; i++, pCurPtr++)     {         //        if ((*pCurPtr & 0xFFFFFF00) == 0)    //将黑色变成透明         if (*pCurPtr == 0xffffff)         {             uint8_t* ptr = (uint8_t*)pCurPtr;             ptr[0] =0;         }                   //改成下面的代码，会将图片转成灰度         /*uint8_t* ptr = (uint8_t*)pCurPtr;          // gray = red * 0.11 + green * 0.59 + blue * 0.30          uint8_t gray = ptr[3] * 0.11 + ptr[2] * 0.59 + ptr[1] * 0.30;          ptr[3] = gray;          ptr[2] = gray;          ptr[1] = gray;*/     }           // 将内存转成image     CGDataProviderRef dataProvider = CGDataProviderCreateWithData(NULL, rgbImageBuf, bytesPerRow * imageHeight,/*ProviderReleaseData**/NULL);     CGImageRef imageRef = CGImageCreate(imageWidth, imageHeight, 8,32, bytesPerRow, colorSpace,                                         kCGImageAlphaLast | kCGBitmapByteOrder32Little, dataProvider,                                         NULL, true,kCGRenderingIntentDefault);     CGDataProviderRelease(dataProvider);           UIImage* resultUIImage = [UIImage imageWithCGImage:imageRef];           // 释放     CGImageRelease(imageRef);     CGContextRelease(context);     CGColorSpaceRelease(colorSpace);     // free(rgbImageBuf) 创建dataProvider时已提供释放函数，这里不用free           return resultUIImage; }

2.截图图片

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CGRect rect ;     //签名事件没有发生     if(min == 0&&max == 0)     {         rect =CGRectMake(0,0, 0, 0);     }     else//签名发生     {         rect =CGRectMake(min-3,0, max-min+6,self.frame.size.height);     }     CGImageRef imageRef =CGImageCreateWithImageInRect([image CGImage], rect);     UIImage * img = [UIImage imageWithCGImage:imageRef];     //添加水印     UIImage *lastImage = [self addText:img text:self.showMessage];     CGImageRelease(imageRef);     [self setNeedsDisplay];

3.压缩

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//压缩图片,最长边为128(根据不同的比例来压缩) - (UIImage *)scaleToSize:(UIImage *)img {     CGRect rect ;     CGFloat imageWidth = img.size.width;     //判断图片宽度     if(imageWidth >= 128)     {         rect =CGRectMake(0,0, 128, self.frame.size.height);     }     else     {         rect =CGRectMake(0,0, img.size.width,self.frame.size.height);               }     CGSize size = rect.size;     UIGraphicsBeginImageContext(size);     [img drawInRect:rect];     UIImage* scaledImage =UIGraphicsGetImageFromCurrentImageContext();     UIGraphicsEndImageContext();     //此处注释是为了防止该签名图片被保存到本地     //    UIImageWriteToSavedPhotosAlbum(scaledImage,nil, nil, nil);     [self setNeedsDisplay];     return scaledImage; }

剩下的,都是一些细节问题,根据不同的项目进行不同的修改就好.

自己做的demo效果