Rotating Bitmaps !!!!

[Adno]

Im using this method needless to say is not working and need some help. void rotateb(Bitmap* image, HDC dc){ Graphics graphics(dc); Bitmap* SrcBitmap1 = image; Color mc; int angle=45; //45° for example //Convert degrees to radians float radians=(2*3.1416*angle)/360; float cosine=(float)cos(radians); float sine=(float)sin(radians); float Point1x=(-SrcBitmap1->GetHeight()*sine); float Point1y=(SrcBitmap1->GetHeight()*cosine); float Point2x=(SrcBitmap1->GetWidth()*cosine-SrcBitmap1->GetHeight()*sine); float Point2y=(SrcBitmap1->GetHeight()*cosine+SrcBitmap1->GetWidth()*sine); float Point3x=(SrcBitmap1->GetWidth()*cosine); float Point3y=(SrcBitmap1->GetWidth()*sine); float minx=min(0,min(Point1x,min(Point2x,Point3x))); float miny=min(0,min(Point1y,min(Point2y,Point3y))); float maxx=max(Point1x,max(Point2x,Point3x)); float maxy=max(Point1y,max(Point2y,Point3y)); int DestBitmapWidth=(int)ceil(fabs(maxx)-minx); int DestBitmapHeight=(int)ceil(fabs(maxy)-miny); Bitmap* DestBitmap = new Bitmap(DestBitmapWidth, DestBitmapHeight); //---------- for(int x=0;x=0&&SrcBitmapxGetWidth() && SrcBitmapy>= 0 && SrcBitmapyGetHeight()) { SrcBitmap1->GetPixel(SrcBitmapx,SrcBitmapy,&mc); DestBitmap->SetPixel(x,y,mc); } } } graphics.DrawImage(DestBitmap,0, 0); <-- this does not //graphics.DrawImage(SrcBitmap1,0,0); <-- this displays } Thank you

[rrrado]

what does it display? Try to set some pixels in destination bmp with some constatnt color to check if there is problem in rotation alghoritm or displaying

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rrrado

[Mark Salsbery]

Also, if you aren't required to write the rotation code yourself, GDI+ will do it for you :) Mark

"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder

[Adno]

hi the GDI+ i find is not very precise Mark i mean the image center shifts, and you have to draw the image then rotate the DC then draw it again you end up with two images and a rotated DC lol the method i posted is skipping the second for loop for some reason :wtf: thanks for your replies... back to digging :)

[Mark Salsbery]

hmm I've found it to be precise. Controlling the image center is easy handled. I'm not sure what you mean by rotating a DC and ending up with two images - It uses pretty much the same technique you are using. Check this out (if you want to :)). This spins an image (in a window, so you can watch) around its center point (like a propellor LOL) at 5 degree increments...

Gdiplus::Bitmap SrcBitmap(L"C:\\test.bmp", FALSE);

Graphics DstGraphics(*this); // use an appropriate HWND here

REAL angle = 0.0f;
for (int i = 0; i < 200; ++i)
{
DstGraphics.ResetTransform();
DstGraphics.RotateTransform(angle);
DstGraphics.TranslateTransform(SrcBitmap.GetWidth() / 2.0f, SrcBitmap.GetWidth() / 2.0f, MatrixOrderAppend);
DstGraphics.DrawImage(&SrcBitmap, -((INT)SrcBitmap.GetWidth() / 2), -((INT)SrcBitmap.GetHeight() / 2),
SrcBitmap.GetWidth(), SrcBitmap.GetHeight());

angle += 5.0f;
if (angle >= 360.0f)
angle -= 360.0f;

//::Sleep(70);
}

"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder

[Adno]

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