Get the coordinates of the limits of a text with Delphi - delphi

Question

Hi I use the follow code to draw a rotate text in my Delphi application. The user can choose if use or not use GDI+ to draw the text:
procedure TForm1.Button1Click(Sender: TObject);
var
MyLogFont: TLogFont;
MyFont: HFont;
t: string;
ff: IGPFontfamily;
ft: IGPFont;
br: IGPSolidBrush;
gr: IGPGraphics;
pp: TGPPointF;
Pen: IGPPen;
begin
t := 'Hello';
if not DrawUsingGDIP.Checked then
begin
// Draw using GDI
FillChar(MyLogFont, Sizeof(MyLogFont), 0);
with MyLogFont do
begin
lfHeight:=0;
lfWidth:=0;
lfEscapement:=-StrToInt(Edit1.Text)*10;
lfOrientation:=-StrToInt(Edit1.Text)*10;
lfWeight:=FW_NORMAL;
lfItalic:=0;
lfUnderline:=0;
lfStrikeOut:=0;
lfCharSet:=DEFAULT_CHARSET;
lfOutPrecision:=OUT_DEFAULT_PRECIS;
lfClipPrecision:=CLIP_DEFAULT_PRECIS;
lfQuality:=DEFAULT_QUALITY;
lfPitchAndFamily:=1;
end;
MyFont:=CreateFontIndirect(MyLogFont);
Form1.Canvas.Font.Handle:=MyFont;
Form1.Canvas.Font.Name := 'Arial';
Form1.Canvas.Font.Size := 13;
Form1.Canvas.TextOut(103, 100, t);
end
else
begin
// Draw using GDI+
Pen := TGPPen.Create($FF000000);
ff := TGPFontFamily.Create('Arial');
ft := TGPFont.Create(ff, 16, FontStyleRegular, UnitPixel);
br := TGPSolidBrush.Create(TGPColor.Red);
gr := TGPGraphics.Create(Form1.Canvas.Handle);
gr.SetTextRenderingHint(TextRenderingHintAntiAlias);
gr.TranslateTransform(100.0, 100.0);
gr.RotateTransform(StrToInt(Edit1.Text));
pp := TGPPointF.Create(0, 0);
gr.DrawString(t, ft, pp, br);
gr.ResetTransform;
end;
end;
Now I need know (if possible without draw the text) the coordinates of the vertices of the rectangle that bounds the text (see the image):
Is there a simple way to get these coordinates both with and without use GDI+ library?

Answer 1

For the GDI implementation you can use something like
tsiz := Form1.Canvas.TextExtent(t); // tsiz : tagSIZE
ang := (2.0*Pi*StrToInt(Edit1.Text))/360; // ang : double
tpts[0].X := 100; // tpts : Array[0..4] of TPoint
tpts[0].Y := 100;
tpts[1].X := 100 + Round(tsiz.cx * Cos(ang));
tpts[1].Y := 100 + Round(tsiz.cx * Sin(ang));
tpts[2].X := tpts[1].X - Round(tsiz.cy*Sin(ang));
tpts[2].Y := tpts[1].Y + Round(tsiz.cy*Cos(ang));
tpts[3].X := tpts[0].X - Round(tsiz.cy*Sin(ang));
tpts[3].Y := tpts[0].Y + Round(tsiz.cy*Cos(ang));
tpts[4] := tpts[0];
//tpts now contains corner points of the bounding rect
Form1.Canvas.TextOut(100, 100, t); // draw text
Form1.Canvas.Polyline(tpts); // draw bounding rect
for GDI+ it's a lot easier
sft := TGPStringFormat.GenericDefault; // sft : IGPStringFormat
mRect := gr.MeasureString(t, ft, pp, sft); // mRect : TGPRectF
// do this after transforms
// mRect is now the bounding rect
gr.DrawRectangle(Pen,mRect);
// mRect is transformed by DrawRectangle - coordinates can be
// calculated in the same way as the GDI case where
// mRect.Width -> tsiz.cx and mRect.Height -> tsiz.cy