我再选一张图片画的时候,之前画的图片就没有了,如何保留之前画的图片?又如何清楚其中任何一张图片?
procedure TForm1.PaintBox1MouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
x1 := X;
y1 := Y;
flag := True;
end;procedure TForm1.PaintBox1MouseMove(Sender: TObject; Shift: TShiftState; X,
Y: Integer);
begin
if flag then
begin
DrawFocusRect(Canvas.Handle, rt);
rt := Rect(x1, y1, X, Y);
DrawFocusRect(Canvas.Handle, rt);
end;
end;procedure TForm1.PaintBox1MouseUp(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
if flag then
begin
rt := Rect(x1, y1, X, Y);
flag := False;
Repaint;
end;
end;procedure TForm1.PaintBox1Paint(Sender: TObject);
var
g: TGPGraphics;
begin
g := TGPGraphics.Create(PaintBox1.Canvas.Handle);
if rt.Right > 0 then g.DrawImage(img, MakeRect(rt));
g.Free;
end;procedure TForm1.Button1Click(Sender: TObject);
begin
if opendialog1.execute then
Edit1.Text := opendialog1.filename;
img := TGPImage.Create(Edit1.Text);
DoubleBuffered := True;
end;
procedure TForm1.PaintBox1MouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
x1 := X;
y1 := Y;
flag := True;
end;procedure TForm1.PaintBox1MouseMove(Sender: TObject; Shift: TShiftState; X,
Y: Integer);
begin
if flag then
begin
DrawFocusRect(Canvas.Handle, rt);
rt := Rect(x1, y1, X, Y);
DrawFocusRect(Canvas.Handle, rt);
end;
end;procedure TForm1.PaintBox1MouseUp(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
if flag then
begin
rt := Rect(x1, y1, X, Y);
flag := False;
Repaint;
end;
end;procedure TForm1.PaintBox1Paint(Sender: TObject);
var
g: TGPGraphics;
begin
g := TGPGraphics.Create(PaintBox1.Canvas.Handle);
if rt.Right > 0 then g.DrawImage(img, MakeRect(rt));
g.Free;
end;procedure TForm1.Button1Click(Sender: TObject);
begin
if opendialog1.execute then
Edit1.Text := opendialog1.filename;
img := TGPImage.Create(Edit1.Text);
DoubleBuffered := True;
end;
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