Will you? The image is not correct. The angle is random.

Will you? The image is not correct. The angle is random Delphi/Windows SDK/API.
Http://www.delphi2007.net/DelphiMultimedia/html/delphi_2006120616581283.html
For example, yes ~~~ Please provide the information for you later ~~
My score is exhausted.

What controls are used to display graphs? Timage? Tpaintbox? Or any canvas?

RoughAlgorithmThis is a basic algorithm that allows a graph to multiply A Rotation Transformation Matrix.

Xiexie !! Any canvas

Post the source code snippets in digital image processing and advanced applications for your reference:

Procedure tform1.bmp _ rotate (srcbmp, destbmp: tbitmap; angle: Extended );
VaR
C1x, c1y, c2x, c2y: integer;
P1x, p1y, P2x, p2y: integer;
Radius, N: integer;
ALPHA: extended;
C0, C1, C2, C3: tcolor;
Begin
If srcbmp. width> srcbmp. Height then
Begin
Destbmp. Width: = srcbmp. width;
Destbmp. Height: = srcbmp. width;
End
Else
Destbmp. Width: = srcbmp. height;
Destbmp. Height: = srcbmp. height;
// Convert the angle to the PI value
Angle: = (angle/180) * PI;
// Calculate the center point. You can modify it.
C1x: = srcbmp. Width Div 2;
C1y: = srcbmp. Height Div 2;
C2x: = destbmp. Width Div 2;
C2y: = destbmp. Height Div 2;
// Step number
If c2x <c2y then
N: = c2y
Else
N: = c2x;
Dec (n, 1 );
// Start Rotation
For P2x: = 0 to n do
Begin
For p2y: = 0 to n do
Begin
If P2x = 0 then
ALPHA: = PI/2
Else
ALPHA: = arctan2 (p2y, P2x );
RADIUS: = round (SQRT (P2x * P2x) + (p2y * p2y )));
P1x: = round (radius * Cos (angle + alpha ));
P1y: = round (radius * sin (angle + alpha ));

C0: = srcbmp. Canvas. pixels [c1x + p1x, c1y + p1y];
C1: = srcbmp. Canvas. pixels [c1x-p1x, c1y-p1y];
C2: = srcbmp. Canvas. pixels [c1x + p1y, c1y-p1x];
C3: = srcbmp. Canvas. pixels [c1x-p1y, c1y + p1x];

Destbmp. Canvas. pixels [c2x + P2x, c2y + p2y]: = C0;
Destbmp. Canvas. pixels [c2x-P2x, c2y-p2y]: = C1;
Destbmp. Canvas. pixels [c2x + p2y, c2y-P2x]: = c2;
Destbmp. Canvas. pixels [c2x-p2y, c2y + P2x]: = C3;
End;
Application. processmessages
End;
End;

Posted upstairsCodeAlgorithm is acceptable,
However, because destbmp. Canvas. pixels is used for point-by-point access, the speed should be quite slow and the effect is not satisfactory.
It is faster to change to scanline.

3ks