Problem with drawing and deleting rectangle
lazarus / 39-Graphics

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Tomi · 2024-11-06 14:32

Hello experts!

I would like draw a rectangle on images in my program with
DrawFocusRect() function, but something is wrong, because I can't
delete the rectangle from its previous place when I have more than one
images.
These images are part of an own type:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i type Ttiles
= class(TCustomimage)  private  publicend;
and a TScrollBox contains them (tilelist).
I load these images as a follows in a mouse event of a button:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i if
(imageOpener.Execute) and (numbersourcetiles<255) thenbegin   
 sourcetileimg:=TPicture.Create;   
 sourcetileimg.LoadFromFile(imageOpener.FileName);     //   
 setlength(tile,numbersourcetiles+1);   
 tile[numbersourcetiles]:=Ttiles.Create(tilelist);   
 tile[numbersourcetiles].Parent:=tilelist;   
 tile[numbersourcetiles].OnMouseUp:=@srctileclick;   
 tile[numbersourcetiles].OnPaint:=@tilePaint;     if
numbersourcetiles>0 then tile[numbersourcetiles].Top:=tile[numbersourc
etiles-1].Top+tile[numbersourcetiles-1].height+2;   
 tile[numbersourcetiles].width:=sourcetileimg.width;   
 tile[numbersourcetiles].height:=sourcetileimg.height;     tile[number
sourcetiles].canvas.copyrect(Rect(0,0,tile[numbersourcetiles].width,ti
le[numbersourcetiles].height),sourcetileimg.bitmap.canvas,Rect(0,0,sou
rcetileimg.width,sourcetileimg.height));     inc(numbersourcetiles); 
  freeandnil(sourcetileimg);end;
This is the srctileclick function:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.srctileclick(Sender: TObject;  Button: TMouseButton; Shift:
TShiftState; X, Y: Integer);var i: byte;begin  if numbersourcetiles>0
then  begin    for i:=0 to numbersourcetiles-1 do    begin         if
(X>=tile[i].Left) and (X<=tile[i].Left+tile[i].width) and ((ScreenToCl
ient(mouse.cursorpos).Y+tilelist.VertScrollBar.Position)-
tilelist.Top>=tile[i].Top) and ((ScreenToClient(mouse.cursorpos).Y+til
elist.VertScrollBar.Position)-
tilelist.Top<=tile[i].Top+tile[i].height) then         begin         
 if thereistiletoput=true then            begin               
 FreeAndNil(tiletoput);                 thereistiletoput:=false;     
     end;            if (GetKeyState(VK_CONTROL) and $80)<>0 then
//Assign tile to grid:            begin                 X:=tile[i].Scr
eenToClient(mouse.cursorpos).X-
(tile[i].ScreenToClient(mouse.cursorpos).X mod tilewidth);           
    Y:=tile[i].ScreenToClient(mouse.cursorpos).Y-
(tile[i].ScreenToClient(mouse.cursorpos).Y mod tileheight);          
end;            tilex:=X;            tiley:=Y;           
tiletoput:=Tbitmap.Create;            tiletoput.width:=tilewidth;    
      tiletoput.height:=tileheight;            tiletoput.canvas.copyre
ct(Rect(0,0,tilewidth,tileheight),tile[i].canvas,Rect(tilex,tiley,tile
x+tilewidth,tiley+tileheight));            thereistiletoput:=true;   
       actualtileimage:=i;           
tile[actualtileimage].invalidate;            Break;         end;   
end;  end;end;
And the tilePaint function:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.tilePaint(Sender: TObject);var fromx,fromy: word;begin  if
thereistiletoput=true then  begin     if (GetKeyState(VK_CONTROL) and
$80)<>0 then     begin         fromx:=tilex-(tilex mod tilewidth);   
    fromy:=tiley-(tiley mod tileheight);     end     else     begin  
     fromx:=tilex;         fromy:=tiley;     end;     tile[actualtilei
mage].canvas.drawfocusrect(Rect(fromx,fromy,fromx+tilewidth,fromy+tile
height));  end;end;
So, I would like put piece of images from an image onto the other's
canvas and I would like make visual this piece for the user with this
rectangle, but when I clicking the image, many rectangles remain on
them.
What should I do? Is it possible to delete those unnecessary
rectangles?