Symbian下16位bmp图像缩放_tvp怎么缩小图像-优快云博客

本文介绍了一种用于32位图像数据的双线性插值缩放算法，包括自定义的颜色结构Color32及图像数据引用结构TPixels32Ref。通过计算像素之间的加权平均值来实现高质量的图像放大或缩小。

程序移植与 http://blog.youkuaiyun.com/housisong/archive/2006/12/21/1452249.aspx

/* * Color32.h * * Created on: 2009-4-29 * Author: flashtao */ #ifndef COLOR32_H_ #define COLOR32_H_ //base type typedef char Int8; typedef unsigned char UInt8; typedef short Int16; typedef unsigned short UInt16; typedef long Int32; typedef unsigned long UInt32; //32bitARGB颜色类型 //16bit 应该是 565型的！ struct Color32 { union { UInt16 rgb; struct { UInt16 b:5; UInt16 g:6; UInt16 r:5; }; }; inline Color32(){} inline Color32(const Color32& color32):rgb(color32.rgb){} inline explicit Color32(const UInt32 color32):rgb(color32){} inline bool operator ==(const Color32& color32) const { return rgb==color32.rgb; } inline bool operator !=(const Color32& color32) const{ return !((*this)==color32); } }; //图像数据区的描述信息 struct TPixels32Ref { public: Color32* pdata; //图像数据区首地址即 y==0行的颜色首地址 long byte_width; //一行图像数据的字节宽度正负值都有可能 long width; //图像宽度 long height; //图像高度 inline TPixels32Ref() :pdata(0),byte_width(0),width(0),height(0){} inline TPixels32Ref(const TPixels32Ref& ref) :pdata(ref.pdata),byte_width(ref.byte_width),width(ref.width),height(ref.height){} //访问(x,y)坐标处的颜色 inline Color32& pixels(const long x,const long y) const { return getLinePixels(y)[x]; } //得到y行的颜色首地址 inline Color32* getLinePixels(const long y) const { return (Color32*) ( ((UInt8*)pdata) + byte_width*y ); } //是否是空图像区 inline bool getIsEmpty()const { return ((width<=0)||(height<=0)); } //将pline指向下一行颜色 inline void nextLine(Color32*& pline)const { ((UInt8*&)pline)+=byte_width; } //坐标边界饱和如果(x,y)坐标在图片数据区外,(x,y)值会被设置到图片最近的边界内,并返回false(否则什么也不做,返回true) //警告! 图片区域不能为空 inline bool clipToBorder(long& x, long& y)const { bool isIn = true; if (x < 0) { isIn = false; x = 0; } else if (x >= width) { isIn = false; x = width - 1; } if (y < 0) { isIn = false; y = 0; } else if (y >= height) { isIn = false; y = height - 1; } return isIn; } //获取一个点的颜色,默认执行边界饱和测试当坐标超出区域的时候返回的颜色为最近的边界上的颜色值并且其alpha通道置零 //警告! 图片区域不能为空速度很慢 inline Color32 getPixelsBorder(long x, long y) const { bool isInPic = clipToBorder(x,y); Color32 result = pixels(x,y); return result; } }; #endif /* COLOR32_H_ */

void CZoom16AppView::Zoom(CFbsBitmap* Dst, CFbsBitmap* src) { TPixels32Ref srcPic; TPixels32Ref dstPic; src->LockHeap(); srcPic.pdata=(Color32*)(src->DataAddress()); srcPic.width=src->SizeInPixels().iWidth; srcPic.height=src->SizeInPixels().iHeight; srcPic.byte_width=srcPic.width*sizeof(Color32); src->UnlockHeap(); Dst->LockHeap(); dstPic.pdata=(Color32*)(Dst->DataAddress()); dstPic.width=Dst->SizeInPixels().iWidth; dstPic.height=Dst->SizeInPixels().iHeight; dstPic.byte_width=dstPic.width*sizeof(Color32); Dst->UnlockHeap(); Dst->LockHeap(); src->LockHeap(); PicZoom_Bilinear0(dstPic,srcPic); // PicZoom_Bilinear1(dstPic,srcPic); // PicZoom_Bilinear2(dstPic,srcPic); src->UnlockHeap(); Dst->UnlockHeap(); } void CZoom16AppView::Bilinear1(const TPixels32Ref& pic,const long x_16,const long y_16,Color32* result) { long x=x_16>>16; long y=y_16>>16; Color32 Color0=pic.getPixelsBorder(x,y); Color32 Color2=pic.getPixelsBorder(x+1,y); Color32 Color1=pic.getPixelsBorder(x,y+1); Color32 Color3=pic.getPixelsBorder(x+1,y+1); unsigned long u_8=(x_16 & 0xFFFF)>>8; unsigned long v_8=(y_16 & 0xFFFF)>>8; unsigned long pm3_16=(u_8*v_8); unsigned long pm2_16=(u_8*(unsigned long)(255-v_8)); unsigned long pm1_16=(v_8*(unsigned long)(255-u_8)); unsigned long pm0_16=((255-u_8)*(255-v_8)); result->r=(UInt8)((pm0_16*Color0.r+pm1_16*Color1.r+pm2_16*Color2.r+pm3_16*Color3.r)>>16); result->g=(UInt8)((pm0_16*Color0.g+pm1_16*Color1.g+pm2_16*Color2.g+pm3_16*Color3.g)>>16); result->b=(UInt8)((pm0_16*Color0.b+pm1_16*Color1.b+pm2_16*Color2.b+pm3_16*Color3.b)>>16); } void CZoom16AppView::PicZoom_Bilinear1(const TPixels32Ref& Dst,const TPixels32Ref& Src) { if ( (0==Dst.width)||(0==Dst.height) ||(0==Src.width)||(0==Src.height)) return; long xrIntdouble_16=((Src.width)<<16)/Dst.width+1; long yrIntdouble_16=((Src.height)<<16)/Dst.height+1; const long csDErrorX=-(1<<15)+(xrIntdouble_16>>1); const long csDErrorY=-(1<<15)+(yrIntdouble_16>>1); long dst_width=Dst.width; Color32* pDstLine=Dst.pdata; long srcy_16=csDErrorY; long y; for (y=0;y<Dst.height;++y) { long srcx_16=csDErrorX; for (long x=0;x<dst_width;++x) { Bilinear1(Src,srcx_16,srcy_16,&pDstLine[x]); //border srcx_16+=xrIntdouble_16; } srcy_16+=yrIntdouble_16; ((UInt8*&)pDstLine)+=Dst.byte_width; } }