Graphics - Working with TCanvas/fr
English · Français · Italiano · Русский
Utilisation de la police d'IHM par défaut
Cela peut être fait avec ce simple code
SelectObject(Canvas.Handle, GetStockObject(DEFAULT_GUI_FONT));Dessin d'un texte Drawing limité en largeur
Employez la routine DrawText, d'abord avec DT_CALCRECT puis sans cela.
// First calculate the text size then draw it
TextBox := Rect(0, currentPos.Y, Width, High(Integer));
DrawText(ACanvas.Handle, PChar(Text), Length(Text),
TextBox, DT_WORDBREAK or DT_INTERNAL or DT_CALCRECT);
DrawText(ACanvas.Handle, PChar(Text), Length(Text),
TextBox, DT_WORDBREAK or DT_INTERNAL);Dessin de texte avec des contours vifs (sans antialiasing)
Certains ensemble de widgets supportent cela à travers :
Canvas.Font.Quality := fqNonAntialiased;Certains ensembles de widgets tel GTK2 ne supportent pas cela et peignent toujours avec l'antialiasing, Voici une simple procédure pour dessiner du texte sans sous GTK2. Il ne prend pas en compte tous les cas, mais il donne une idée:
procedure PaintAliased(Canvas: TCanvas; x,y: integer; const TheText: string);
var
w,h: integer;
IntfImg: TLazIntfImage;
Img: TBitmap;
dy: Integer;
dx: Integer;
col: TFPColor;
FontColor: TColor;
c: TColor;
begin
w:=0;
h:=0;
Canvas.GetTextSize(TheText,w,h);
if (w<=0) or (h<=0) then exit;
Img:=TBitmap.Create;
IntfImg:=nil;
try
// paint text to a bitmap
Img.Masked:=true;
Img.SetSize(w,h);
Img.Canvas.Brush.Style:=bsSolid;
Img.Canvas.Brush.Color:=clWhite;
Img.Canvas.FillRect(0,0,w,h);
Img.Canvas.Font:=Canvas.Font;
Img.Canvas.TextOut(0,0,TheText);
// get memory image
IntfImg:=Img.CreateIntfImage;
// replace gray pixels
FontColor:=ColorToRGB(Canvas.Font.Color);
for dy:=0 to h-1 do begin
for dx:=0 to w-1 do begin
col:=IntfImg.Colors[dx,dy];
c:=FPColorToTColor(col);
if c<>FontColor then
IntfImg.Colors[dx,dy]:=colTransparent;
end;
end;
// create bitmap
Img.LoadFromIntfImage(IntfImg);
// paint
Canvas.Draw(x,y,Img);
finally
IntfImg.Free;
Img.Free;
end;
end;From the Free Pascal wiki, page "Graphics - Working with TCanvas/fr", as it stood on 2020-02-16 after a change by Trev, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's Licensing page. If you have concerns about this material, message the admin.
Edited on wiki.freepascal.org by 2 people, 2016–2020
From the official wiki's backup of 26 May 2024: who edited this page there, and when. Edits made there after that date were not recorded, and the earlier versions are not shown here; the main page says why.
| When | Who | What changed |
|---|---|---|
| E-ric | Created page | |
| E-ric | Dessin de texte avec des contours vifs (sans antialiasing) (minor) | |
| Trev | Fixed syntax highlighting (minor) |
Talk about this page
Nobody has opened a bench for this page yet. Sign in to open one.
