位图旋转产生的问题
在旋转位图的时候，在四个角的地方出现黑色背景，怎么解决啊。
代码如下
[code=C/C++][/code]
void CSMNSView::RotateBitmap(HDC dcSrc, int SrcWidth, int SrcHeight, double angle, HDC pDC)
{
double x1,x2,x3;
double y1,y2,y3;
double maxWidth,maxHeight,minWidth,minHeight;
double srcX,srcY;
double sinA,cosA;
double DstWidth;
double DstHeight;
HDC dcDst;//旋转后的内存设备环境
HBITMAP newBitmap;
sinA = sin(angle);
cosA = cos(angle);
x1 = -SrcHeight * sinA;
y1 = SrcHeight * cosA;
x2 = SrcWidth * cosA - SrcHeight * sinA;
y2 = SrcHeight * cosA + SrcWidth * sinA;
x3 = SrcWidth * cosA;
y3 = SrcWidth * sinA;
minWidth = x3>(x1>x2?x2:x1)?(x1>x2?x2:x1):x3;
minWidth = minWidth>0?0:minWidth;
minHeight = y3>(y1>y2?y2:y1)?(y1>y2?y2:y1):y3;
minHeight = minHeight>0?0:minHeight;
maxWidth = x3>(x1>x2?x1:x2)?x3:(x1>x2?x1:x2);
maxWidth = maxWidth>0?maxWidth:0;
maxHeight = y3>(y1>y2?y1:y2)?y3:(y1>y2?y1:y2);
maxHeight = maxHeight>0?maxHeight:0;
DstWidth = maxWidth - minWidth;
DstHeight = maxHeight - minHeight;
dcDst = CreateCompatibleDC(dcSrc);
newBitmap = CreateCompatibleBitmap(dcSrc,(int)DstWidth,(int)DstHeight);
SelectObject(dcDst,newBitmap);
for( int I = 0 ;I<DstHeight;I++)
{
for(int J = 0 ;J< DstWidth;J++)
{
srcX = (J + minWidth) * cosA + (I + minHeight) * sinA;
srcY = (I + minHeight) * cosA - (J + minWidth) * sinA;
if( (srcX >= 0) && (srcX <= SrcWidth) &&(srcY >= 0) && (srcY <= SrcHeight))
{
BitBlt(dcDst, J, I, 1, 1, dcSrc,(int)srcX, (int)srcY, SRCCOPY);
}
}
}
//显示旋转后的位图
TransparentBlt(pDC,m_ptOrigin.x-bmInfo.bmWidth/2,m_ptOrigin.y-bmInfo.bmHeight/2,
(int)DstWidth,(int)DstHeight,dcDst,0,0,
(int)DstWidth,(int)DstHeight,RGB(255,255,255));
//BitBlt(pDC,150,100,(int)DstWidth,(int)DstHeight,dcDst,0,0,SRCCOPY);
DeleteObject(newBitmap);
DeleteDC(dcDst);
[解决办法]
画之前
::SetStretchBltMode(pDC->GetSafeHwnd(),HALFTONE);
看看
[解决办法]
用OpenCV来实现图像任意角度旋转很方便。
http://blog.csdn.net/fengbingchun/article/details/6021622
[解决办法]
先得到背景数据，旋转后，把背景数据[注意坐标位置]再填入黑的部分即可。
[解决办法]
你要实现什么功能？可以在周围加上框框什么的，或者在其他地方呈现
