I need to rotate an object inside a canvas in Delphi.
Example rotate by 90 degrees. Text I get is easy, but I have to be able to do it for any type drawn object.
As for an image drawn on the canvas or a geometric figure drawn by canvas .
Example:
Image1.canvas.font.orientation := 900; //equivale rotacionar em 90 gráus.
Only I wanted for any object drawn on canvas, not just texts. I only get text with the example above.
I did it once in the following way, I added a text in it and rotated the image.
procedure TForm2.ConvTextOut(CV: TCanvas; const sText: String; x, y,
angle: integer);
var
LogFont: TLogFont;
SaveFont: TFont;
begin
SaveFont := TFont.Create;
SaveFont.Assign(CV.Font);
GetObject(SaveFont.Handle, sizeof(TLogFont), @LogFont);
with LogFont do
begin
lfEscapement := angle *10;
lfPitchAndFamily := FIXED_PITCH or FF_DONTCARE;
end;
CV.Font.Handle := CreateFontIndirect(LogFont);
SetBkMode(CV.Handle, TRANSPARENT);
CV.TextOut(x, y, sText);
CV.Font.Assign(SaveFont);
SaveFont.Free;
end;
ConvTextOut(Origem.Canvas, label1.caption, 0, 0, 0);
Resultado.Width := Origem.Height;
Resultado.Height := Origem.Width;
Resultado.Update;
for k := 0 to Origem.Width do
for Y := 0 to Origem.Height do
Resultado.Canvas.Pixels[Origem.Height-Y, k] := Origem.Canvas.Pixels[k,Y];
Dude, one way I found on google is bit by bit. I did not know it had to be this way.
procedure Rotate90(Source: TGraphic; Target: TJpegImage);
var
SourceBmp, TargetBmp: TBitmap;
r, c: Integer;
x, y: Integer;
begin
SourceBmp := TBitmap.Create;
SourceBmp.Assign(Source);
TargetBmp := TBitmap.Create;
TargetBmp.Width := SourceBmp.Height;
TargetBmp.Height := SourceBmp.Width;
for r := 0 to SourceBmp.Height - 1 do
begin
for c := 0 to SourceBmp.Width - 1 do
begin
//x := (SourceBmp.Height-1) - r; // -90
//y := c; //-90
x := r; //90
y := (SourceBmp.Width-1) - c; //90
// look into Bitmap.ScanLine for faster pixel access
TargetBmp.Canvas.Pixels[x, y] := SourceBmp.Canvas.Pixels[c, r];
end;
end;
Target.Assign(TargetBmp);
SourceBmp.Free;
TargetBmp.Free;
end;
procedure TForm1.Button1Click(Sender: TObject);
var
Jpeg: TJPEGImage;
begin
Jpeg := TJPEGImage.Create;
Rotate90(Image1.Picture.Graphic, Jpeg);
Image1.Picture.Assign(Jpeg);
Jpeg.Free;
end;
I did not test but it seems correct.
Source: link