Resizing Bar Custom Painting Sample
- 2 minutes to read
You have the following options to paint a resizing bar that is displayed when resizing dock controls:
Custom paint the resizing bar by handling the docking manager’s OnCustomDrawResizingSelection event.
Custom paint the resizing bar for an individual dock control by handling only the control’s OnCustomDrawDockingSelection event.
Refer to the Docking Frame and Resizing Bar Custom Painting topic, for basic information about these events.
The sample code below handles the docking manager’s OnCustomDrawResizingSelection event. For horizontal resizing operations, the resizing bar is painted in the default manner. For vertical resizing operations, the resizing bar is painted using an inverse texture brush.
procedure TForm1.dxDockingManager1CustomDrawResizingSelection(Sender: TdxCustomDockControl; DC: HDC; Zone: TdxZone; ARect: TRect; Erasing: Boolean; var Handled: Boolean);
var
ABrush, AOldBrush: HBRUSH;
Bitmap: TBitmap;
begin
if Zone.Direction = zdVertical then Exit;
Bitmap := TBitmap.Create;
Bitmap.LoadFromFile('d:\SelectionBarTexture.bmp');
ABrush := CreatePatternBrush(Bitmap.Handle);
AOldBrush := SelectObject(DC, ABrush);
try
with ARect do
PatBlt(DC, Left, Top, Right - Left, Bottom - Top, PATINVERT);
Handled := True;
finally
SelectObject(DC, AOldBrush);
DeleteObject(ABrush);
Bitmap.Free;
end;
end;
The image below shows the resulting appearance of the resizing bar.
The following image shows a bitmap that was used as the brush’s pattern. (The image is magnified four times. A red border was not used – it simply shows image boundaries.)
