主要代码
1、拉伸后纹理、顶点坐标的计算
// 获取图片的中间拉伸区域高度: (currentBottom - currentTop)*sliderValue + 0.5;
CGFloat newHeight = (self.currentBottom - self.currentTop) * ((sender.value) + 0.5);</pre>
/**
根据当前控件的尺寸和纹理的尺寸，计算初始纹理、顶点坐标
@param size 原始纹理尺寸
@param startY 中间区域的开始纵坐标位置 0~1
@param endY 中间区域的结束纵坐标位置 0~1
@param newHeight 新的中间区域的高度
*/
- (void)calculateOriginTextureCoordWithTextureSize:(CGSize)size
startY:(CGFloat)startY
endY:(CGFloat)endY
newHeight:(CGFloat)newHeight {
NSLog(@"%f,%f",size.height,size.width);
// 1. 计算拉伸后的宽高比;
CGFloat ratio = (size.height / size.width) *
(self.bounds.size.width / self.bounds.size.height);
CGFloat rr = self.bounds.size.width / self.bounds.size.height;
// 2. 宽度=纹理本身宽度;
CGFloat textureWidth = self.currentTextureWidth;
// 3. 高度=纹理高度*radio(宽高比)
CGFloat textureHeight = textureWidth * ratio;
NSLog(@"%f,%f,%f,%f",newHeight,endY,startY,textureHeight);
// 4. 拉伸量 (newHeight - (endY-startY)) * 纹理高度;
CGFloat delta = (newHeight - (endY - startY)) * textureHeight;
// 5. 判断纹理高度+拉伸量是否超出最大值1
if (textureHeight + delta >= 1) {
delta = 1 - textureHeight;
newHeight = delta / textureHeight + (endY - startY);
}
// 6. 纹理4个角的顶点
// 左上角
GLKVector3 pointLT = {-textureWidth, textureHeight + delta, 0};
// 右上角
GLKVector3 pointRT = {textureWidth, textureHeight + delta, 0};
// 左下角
GLKVector3 pointLB = {-textureWidth, -textureHeight - delta, 0};
// 右下角
GLKVector3 pointRB = {textureWidth, -textureHeight - delta, 0};
// 中间矩形区域的顶点
CGFloat tempStartYCoord = textureHeight - 2 * textureHeight * startY;
CGFloat tempEndYCoord = textureHeight - 2 * textureHeight * endY;
CGFloat startYCoord = MIN(tempStartYCoord, textureHeight);
CGFloat endYCoord = MAX(tempEndYCoord, -textureHeight);
// 中间部分左上角
GLKVector3 centerPointLT = {-textureWidth, startYCoord + delta, 0};
// 中间部分右上角
GLKVector3 centerPointRT = {textureWidth, startYCoord + delta, 0};
// 中间部分左下角
GLKVector3 centerPointLB = {-textureWidth, endYCoord - delta, 0};
// 中间部分右下角
GLKVector3 centerPointRB = {textureWidth, endYCoord - delta, 0};
// --纹理的上面两个顶点
// 顶点V0的顶点坐标以及纹理坐标;
self.vertices[0].positionCoord = pointRT;
self.vertices[0].textureCoord = GLKVector2Make(1, 1);
// 顶点V1的顶点坐标以及纹理坐标;
self.vertices[1].positionCoord = pointLT;
self.vertices[1].textureCoord = GLKVector2Make(0, 1);
// -- 中间区域的4个顶点
//顶点V2的顶点坐标以及纹理坐标;
self.vertices[2].positionCoord = centerPointRT;
self.vertices[2].textureCoord = GLKVector2Make(1, 1 - startY);
// 顶点V3的顶点坐标以及纹理坐标;
self.vertices[3].positionCoord = centerPointLT;
self.vertices[3].textureCoord = GLKVector2Make(0, 1 - startY);
// 顶点V4的顶点坐标以及纹理坐标;
self.vertices[4].positionCoord = centerPointRB;
self.vertices[4].textureCoord = GLKVector2Make(1, 1 - endY);
// 顶点V5的顶点坐标以及纹理坐标;
self.vertices[5].positionCoord = centerPointLB;
self.vertices[5].textureCoord = GLKVector2Make(0, 1 - endY);
// 纹理的下面两个顶点
// 顶点V6的顶点坐标以及纹理坐标;
self.vertices[6].positionCoord = pointRB;
self.vertices[6].textureCoord = GLKVector2Make(1, 0);
// 顶点V7的顶点坐标以及纹理坐标;
self.vertices[7].positionCoord = pointLB;
self.vertices[7].textureCoord = GLKVector2Make(0, 0);
// 保存临时值
self.currentTextureStartY = startY;
self.currentTextureEndY = endY;
self.currentNewHeight = newHeight;
}
2、图片保存至相册
// 从帧缓存区中获取纹理图片文件，获取当前的渲染结果
- (UIImage *)createResult {
// 1. 根据屏幕上显示结果, 重新获取顶点/纹理坐标
[self resetTextureWithOriginWidth:self.currentImageSize.width
originHeight:self.currentImageSize.height
topY:self.currentTextureStartY
bottomY:self.currentTextureEndY
newHeight:self.currentNewHeight];
// 2.绑定帧缓存区;
glBindFramebuffer(GL_FRAMEBUFFER, self.tmpFrameBuffer);
// 3.获取新的图片Size
CGSize imageSize = [self newImageSize];
// 4.从帧缓存中获取拉伸后的图片;
UIImage *image = [self imageFromTextureWithWidth:imageSize.width height:imageSize.height];
// 5. 将帧缓存绑定0,清空;
glBindFramebuffer(GL_FRAMEBUFFER, 0);
// 6. 返回拉伸后的图片
return image;
}
/**
根据当前屏幕上的显示，重新创建纹理
@param originWidth 纹理的原始实际宽度
@param originHeight 纹理的原始实际高度
@param topY 0 ~ 1，拉伸区域的顶边的纵坐标
@param bottomY 0 ~ 1，拉伸区域的底边的纵坐标
@param newHeight 0 ~ 1，拉伸区域的新高度
*/
- (void)resetTextureWithOriginWidth:(CGFloat)originWidth
originHeight:(CGFloat)originHeight
topY:(CGFloat)topY
bottomY:(CGFloat)bottomY
newHeight:(CGFloat)newHeight {
// 1.新的纹理尺寸(新纹理图片的宽高)
GLsizei newTextureWidth = originWidth;
GLsizei newTextureHeight = originHeight * (newHeight - (bottomY - topY)) + originHeight;
// 2.高度变化百分比
CGFloat heightScale = newTextureHeight / originHeight;
// 3.在新的纹理坐标下，重新计算 topY、bottomY
CGFloat newTopY = topY / heightScale;
CGFloat newBottomY = (topY + newHeight) / heightScale;
// 4.创建顶点数组与纹理数组(逻辑与calculateOriginTextureCoordWithTextureSize 中关于纹理坐标以及顶点坐标逻辑是一样的)
SenceVertex *tmpVertices = malloc(sizeof(SenceVertex) * kVerticesCount);
tmpVertices[0] = (SenceVertex){{-1, 1, 0}, {0, 1}};
tmpVertices[1] = (SenceVertex){{1, 1, 0}, {1, 1}};
tmpVertices[2] = (SenceVertex){{-1, -2 * newTopY + 1, 0}, {0, 1 - topY}};
tmpVertices[3] = (SenceVertex){{1, -2 * newTopY + 1, 0}, {1, 1 - topY}};
tmpVertices[4] = (SenceVertex){{-1, -2 * newBottomY + 1, 0}, {0, 1 - bottomY}};
tmpVertices[5] = (SenceVertex){{1, -2 * newBottomY + 1, 0}, {1, 1 - bottomY}};
tmpVertices[6] = (SenceVertex){{-1, -1, 0}, {0, 0}};
tmpVertices[7] = (SenceVertex){{1, -1, 0}, {1, 0}};
/// 下面开始渲染到纹理的流程
// 1. 生成帧缓存区;
GLuint frameBuffer;
GLuint texture;
// glGenFramebuffers 生成帧缓存区对象名称;
glGenFramebuffers(1, &frameBuffer);
// glBindFramebuffer 绑定一个帧缓存区对象;
glBindFramebuffer(GL_FRAMEBUFFER, frameBuffer);
// 2. 生成纹理ID,绑定纹理;
// glGenTextures 生成纹理ID
glGenTextures(1, &texture);
// glBindTexture 将一个纹理绑定到纹理目标上;
glBindTexture(GL_TEXTURE_2D, texture);
// glTexImage2D 指定一个二维纹理图像;
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, newTextureWidth, newTextureHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
// 3. 设置纹理相关参数
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
// 4. 将纹理图像加载到帧缓存区对象上;
/*
glFramebufferTexture2D (GLenum target, GLenum attachment, GLenum textarget, GLuint texture, GLint level)
target: 指定帧缓冲目标,符合常量必须是GL_FRAMEBUFFER;
attachment: 指定附着纹理对象的附着点GL_COLOR_ATTACHMENT0
textarget: 指定纹理目标, 符合常量:GL_TEXTURE_2D
teture: 指定要附加图像的纹理对象;
level: 指定要附加的纹理图像的mipmap级别，该级别必须为0。
*/
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture, 0);
// 5. 设置视口尺寸
glViewport(0, 0, newTextureWidth, newTextureHeight);
// 6. 获取着色器程序
GLuint program = [LongLegHelper programWithShaderName:@"spring"];
glUseProgram(program);
// 7. 获取参数ID
GLuint positionSlot = glGetAttribLocation(program, "Position");
GLuint textureSlot = glGetUniformLocation(program, "Texture");
GLuint textureCoordsSlot = glGetAttribLocation(program, "TextureCoords");
// 8. 传值
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, self.baseEffect.texture2d0.name);
glUniform1i(textureSlot, 0);
// 9.初始化缓存区
LongLegVertexAttribArrayBuffer *vbo = [[LongLegVertexAttribArrayBuffer alloc] initWithAttribStride:sizeof(SenceVertex) numberOfVertices:kVerticesCount data:tmpVertices usage:GL_STATIC_DRAW];
// 10.准备绘制,将纹理/顶点坐标传递进去;
[vbo prepareToDrawWithAttrib:positionSlot numberOfCoordinates:3 attribOffset:offsetof(SenceVertex, positionCoord) shouldEnable:YES];
[vbo prepareToDrawWithAttrib:textureCoordsSlot numberOfCoordinates:2 attribOffset:offsetof(SenceVertex, textureCoord) shouldEnable:YES];
// 11. 绘制
[vbo drawArrayWithMode:GL_TRIANGLE_STRIP startVertexIndex:0 numberOfVertices:kVerticesCount];
// 12.解绑缓存
glBindFramebuffer(GL_FRAMEBUFFER, 0);
// 13.释放顶点数组
free(tmpVertices);
// 14.保存临时的纹理对象/帧缓存区对象;
self.tmpTexture = texture;
self.tmpFrameBuffer = frameBuffer;
}
// 返回某个纹理对应的 UIImage，调用前先绑定对应的帧缓存
- (UIImage *)imageFromTextureWithWidth:(int)width height:(int)height {
// 1.绑定帧缓存区;
glBindFramebuffer(GL_FRAMEBUFFER, self.tmpFrameBuffer);
// 2.将帧缓存区内的图片纹理绘制到图片上;
int size = width * height * 4;
GLubyte *buffer = malloc(size);
/*
glReadPixels (GLint x, GLint y, GLsizei width, GLsizei height, GLenum format, GLenum type, GLvoid* pixels);
@功能: 读取像素(理解为将已经绘制好的像素,从显存中读取到内存中;)
@参数解读:
参数x,y,width,height: xy坐标以及读取的宽高;
参数format: 颜色格式; GL_RGBA;
参数type: 读取到的内容保存到内存所用的格式;GL_UNSIGNED_BYTE 会把数据保存为GLubyte类型;
参数pixels: 指针,像素数据读取后, 将会保存到该指针指向的地址内存中;
注意: pixels指针,必须保证该地址有足够的可以使用的空间, 以容纳读取的像素数据; 例如一副256 * 256的图像,如果读取RGBA 数据, 且每个数据保存在GLUbyte. 总大小就是 256 * 256 * 4 = 262144字节, 即256M;
int size = width * height * 4;
GLubyte *buffer = malloc(size);
*/
glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
// 使用data和size 数组来访问buffer数据;
/*
CGDataProviderRef CGDataProviderCreateWithData(void *info, const void *data, size_t size, CGDataProviderReleaseDataCallback releaseData);
@功能: 新的数据类型, 方便访问二进制数据;
@参数:
参数info: 指向任何类型数据的指针, 或者为Null;
参数data: 数据存储的地址,buffer
参数size: buffer的数据大小;
参数releaseData: 释放的回调,默认为空;
*/
CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, buffer, size, NULL);
// 每个组件的位数;
int bitsPerComponent = 8;
// 像素占用的比特数4 * 8 = 32;
int bitsPerPixel = 32;
// 每一行的字节数
int bytesPerRow = 4 * width;
// 颜色空间格式;
CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
// 位图图形的组件信息 - 默认的
CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault;
// 颜色映射
CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;
// 3.将帧缓存区里像素点绘制到一张图片上;
/*
CGImageCreate(size_t width, size_t height,size_t bitsPerComponent, size_t bitsPerPixel, size_t bytesPerRow,CGColorSpaceRef space, CGBitmapInfo bitmapInfo, CGDataProviderRef provider,const CGFloat decode[], bool shouldInterpolate,CGColorRenderingIntent intent);
@功能:根据你提供的数据创建一张位图;
注意:size_t 定义的是一个可移植的单位,在64位机器上为8字节,在32位机器上是4字节;
参数width: 图片的宽度像素;
参数height: 图片的高度像素;
参数bitsPerComponent: 每个颜色组件所占用的位数, 比如R占用8位;
参数bitsPerPixel: 每个颜色的比特数, 如果是RGBA则是32位, 4 * 8 = 32位;
参数bytesPerRow :每一行占用的字节数;
参数space:颜色空间模式,CGColorSpaceCreateDeviceRGB
参数bitmapInfo:kCGBitmapByteOrderDefault 位图像素布局;
参数provider: 图片数据源提供者, 在CGDataProviderCreateWithData ,将buffer 转为 provider 对象;
参数decode: 解码渲染数组, 默认NULL
参数shouldInterpolate: 是否抗锯齿;
参数intent: 图片相关参数;kCGRenderingIntentDefault
*/
CGImageRef imageRef = CGImageCreate(width, height, bitsPerComponent, bitsPerPixel, bytesPerRow, colorSpaceRef, bitmapInfo, provider, NULL, NO, renderingIntent);
// 4. 此时的 imageRef 是上下颠倒的，调用 CG 的方法重新绘制一遍，翻转过来
// 创建一个图片context
UIGraphicsBeginImageContext(CGSizeMake(width, height));
CGContextRef context = UIGraphicsGetCurrentContext();
// 将图片绘制上去
CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);
// 从context中获取图片
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
// 结束图片context处理
UIGraphicsEndImageContext();
// 释放buffer
free(buffer);
// 返回图片
return image;
}
网友评论