CODEWITHSUNDEEP
c++gdi
H4cKL0rD
H4cKL0rD

Reputation: 5508

How to rotate Bitmap in windows GDI?

How would I go about rotating a Bitmap in Windows GDI,C++?

Upvotes: 13

Views: 15312

Answers (3)

Jerry Coffin
Jerry Coffin

Reputation: 490623

Another possibility (beyond those already suggested) is to use SetWorldTransform(). This is different in that it is modal and applies to the DC as a whole, not just a single operation. If you want to rotate one bitmap rotated, but other things without rotation, it's probably not your best choice. If you want to draw a number of things rotated, or (especially) if you want to rotate everything you draw (at least into one DC) it can work quite nicely though.

Upvotes: 3

Hans Passant
Hans Passant

Reputation: 942267

You can do it with GDI+ (#include <gdiplus.h>). The Graphics class has the RotateTransform method. That allows arbitrary rotations. Use Image::RotateFlip() if you only need to rotate by 90 degree increments, that's a lot more efficient.

Upvotes: 9

Frank Krueger
Frank Krueger

Reputation: 71053

Sounds like you have to use PlgBlt. Take your rectangle's 4 corners as 2D Points, rotate them, then call PlgBlt.

From MSDN Bitmap Rotation:

To copy a bitmap into a parallelogram; use the PlgBlt function, which performs a bit-block transfer from a rectangle in a source device context into a parallelogram in a destination device context. To rotate the bitmap, an application must provide the coordinates, in world units, to be used for the corners of the parallelogram.

Upvotes: 4

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