asked on

drawing Graphics and mouse position simultaneously

I am using canvas.moveto and canvas.lineto to draw a stepped line that is moving from right to left, by drawing, changing the color to tha background and redrawing. I want to try to follow the line while it is being drawn, and moving, with the mouse, then compare the mouse path with the actual line. Is this possible? The stepped line coordinates are in an array (columns 1 to 4 for starting point and endpoint) and I want the mouse coordinates in the same array (columns 5 and 6).

Can onmousemove be active while already drawing without the mouse?

I need a very urgent answer!!!
Thanks
Delene

esoftbg

Something like that ?

procedure Draw_Canvas_Line(Canvas: TCanvas; P1, P2: TPoint; Cl: TColor);
var
P0: TPoint;
IX: Integer;
IY: Integer;
DX: Integer;
DY: Integer;
T: Extended;
begin
DX := P2.X - P1.X;
DY := P2.Y - P1.Y;
if (DX=0) then
begin
Canvas.Pen.Color := Cl;
if (P1.Y<P2.Y) then
begin
for IY := P1.Y to P2.Y-1 do
begin
Canvas.MoveTo(P1.X, IY);
Canvas.LineTo(P1.X, IY+1);
Sleep(100);
Application.ProcessMessages;
end;
end
else
begin
for IY := P1.Y downto P2.Y-1 do
begin
Canvas.MoveTo(P1.X, IY);
Canvas.LineTo(P1.X, IY-1);
Sleep(100);
Application.ProcessMessages;
end;
end
end
else
if (DY=0) then
begin
Canvas.Pen.Color := Cl;
if (P1.X<P2.X) then
begin
for IX := P1.X to P2.X-1 do
begin
Canvas.MoveTo(IX, P1.Y);
Canvas.LineTo(IX+1, P1.Y);
Sleep(100);
Application.ProcessMessages;
end;
end
else
begin
for IX := P1.X downto P2.X-1 do
begin
Canvas.MoveTo(IX, P1.Y);
Canvas.LineTo(IX-1, P1.Y);
Sleep(100);
Application.ProcessMessages;
end;
end
end
else
begin
T := DY / DX;
Canvas.Pen.Color := Cl;
if (DX>=DY) then
begin
if (P1.X<P2.X) then
begin
for IX := P1.X to P2.X {-1} do
begin
P0.X := IX;
P0.Y := P1.Y + Round((IX - P1.X) * T);
Canvas.MoveTo(P1.X, P1.Y);
Canvas.LineTo(P0.X, P0.Y);
Sleep(100);
Application.ProcessMessages;
end;
end
else
begin
for IX := P1.X downto P2.X {-1} do
begin
P0.X := IX;
P0.Y := P1.Y + Round((IX - P1.X) * T);
Canvas.MoveTo(P1.X, P1.Y);
Canvas.LineTo(P0.X, P0.Y);
Sleep(100);
Application.ProcessMessages;
end;
end;
end
else
begin
if (P1.Y<P2.Y) then
begin
for IY := P1.Y to P2.Y {-1} do
begin
P0.Y := IY;
P0.X := P1.X + Round((IY - P1.Y) / T);
Canvas.MoveTo(P1.X, P1.Y);
Canvas.LineTo(P0.X, P0.Y);
Sleep(100);
Application.ProcessMessages;
end;
end
else
begin
for IY := P1.Y downto P2.Y {-1} do
begin
P0.Y := IY;
P0.X := P1.X + Round((IY - P1.Y) / T);
Canvas.MoveTo(P1.X, P1.Y);
Canvas.LineTo(P0.X, P0.Y);
Sleep(100);
Application.ProcessMessages;
end;
end;
end;
end;
end;

procedure TForm1.SpeedButton1Click(Sender: TObject);
begin
Draw_Canvas_Line(Img.Canvas, Point(8,8), Point(48,120), clBlack);
Draw_Canvas_Line(Img.Canvas, Point(48,120), Point(112,96), clBlack);
Draw_Canvas_Line(Img.Canvas, Point(112,96), Point(120,8), clBlack);
Draw_Canvas_Line(Img.Canvas, Point(120,8), Point(8,8), clBlack);
end;

esoftbg

download a super example from:
page: http://www.geocities.com/esoftbg/
link: Q_21127913.zip

//........

procedure Draw_Canvas_Line(Canvas: TCanvas; P1, P2: TPoint; Cl: TColor; PT: TPoint; Wait: Integer);
var
P0: TPoint;
IX: Integer;
IY: Integer;
DX: Integer;
DY: Integer;
T: Extended;
begin
DX := P2.X - P1.X;
DY := P2.Y - P1.Y;
if (DX=0) then
begin
Canvas.Pen.Color := Cl;
if (P1.Y<P2.Y) then
begin
for IY := P1.Y to P2.Y-1 do
begin
Canvas.MoveTo(P1.X, IY);
Canvas.LineTo(P1.X, IY+1);
SetCursorPos(PT.X + P1.X, PT.Y + IY+1);
Sleep(Wait);
Application.ProcessMessages;
end;
end
else
begin
for IY := P1.Y downto P2.Y+1 do
begin
Canvas.MoveTo(P1.X, IY);
Canvas.LineTo(P1.X, IY-1);
SetCursorPos(PT.X + P1.X, PT.Y + IY-1);
Sleep(Wait);
Application.ProcessMessages;
end;
end
end
else
if (DY=0) then
begin
Canvas.Pen.Color := Cl;
if (P1.X<P2.X) then
begin
for IX := P1.X to P2.X-1 do
begin
Canvas.MoveTo(IX, P1.Y);
Canvas.LineTo(IX+1, P1.Y);
SetCursorPos(PT.X + IX+1, PT.Y + P1.Y);
Sleep(Wait);
Application.ProcessMessages;
end;
end
else
begin
for IX := P1.X downto P2.X+1 do
begin
Canvas.MoveTo(IX, P1.Y);
Canvas.LineTo(IX-1, P1.Y);
SetCursorPos(PT.X + IX-1, PT.Y + P1.Y);
Sleep(Wait);
Application.ProcessMessages;
end;
end
end
else
begin
T := DY / DX;
Canvas.Pen.Color := Cl;
if (DX>=DY) then
begin
if (P1.X<P2.X) then
begin
for IX := P1.X to P2.X {-1} do
begin
P0.X := IX;
P0.Y := P1.Y + Round((IX - P1.X) * T);
Canvas.MoveTo(P1.X, P1.Y);
Canvas.LineTo(P0.X, P0.Y);
SetCursorPos(PT.X + P0.X, PT.Y + P0.Y);
Sleep(Wait);
Application.ProcessMessages;
end;
end
else
begin
for IX := P1.X downto P2.X {-1} do
begin
P0.X := IX;
P0.Y := P1.Y + Round((IX - P1.X) * T);
Canvas.MoveTo(P1.X, P1.Y);
Canvas.LineTo(P0.X, P0.Y);
SetCursorPos(PT.X + P0.X, PT.Y + P0.Y);
Sleep(Wait);
Application.ProcessMessages;
end;
end;
end
else
begin
if (P1.Y<P2.Y) then
begin
for IY := P1.Y to P2.Y {-1} do
begin
P0.Y := IY;
P0.X := P1.X + Round((IY - P1.Y) / T);
Canvas.MoveTo(P1.X, P1.Y);
Canvas.LineTo(P0.X, P0.Y);
SetCursorPos(PT.X + P0.X, PT.Y + P0.Y);
Sleep(Wait);
Application.ProcessMessages;
end;
end
else
begin
for IY := P1.Y downto P2.Y {-1} do
begin
P0.Y := IY;
P0.X := P1.X + Round((IY - P1.Y) / T);
Canvas.MoveTo(P1.X, P1.Y);
Canvas.LineTo(P0.X, P0.Y);
SetCursorPos(PT.X + P0.X, PT.Y + P0.Y);
Sleep(Wait);
Application.ProcessMessages;
end;
end;
end;
end;
end;

procedure TForm1.SpeedButton1Click(Sender: TObject);
var
PT: TPoint;
begin
PT := Form1.Img.ClientToScreen(Point(0, 0));
Draw_Canvas_Line(Img.Canvas, Point(8,8), Point(8,120), clBlack, PT, 48);
Draw_Canvas_Line(Img.Canvas, Point(8,120), Point(112,96), clBlack, PT, 48);
Draw_Canvas_Line(Img.Canvas, Point(112,96), Point(120,8), clBlack, PT, 128);
Draw_Canvas_Line(Img.Canvas, Point(120,8), Point(8,8), clBlack, PT, 48);
end;

Delene_Heukelman

ASKER

No, possibly I did not explain it very well, or I am too inexperienced. I need the mouse coordinates captured to an array while the drawing of the line takes place. The user sees the line that is moving left over the screen, and tries to follow it with the mouse. I want to be able to compare the actual line and the path the mouse followed, so both must be in an array.

I tried to interrupt the line drawing procedure after each section of the stepped line is drawn, with the timer enabled, to capture the onmousemove coordinates and return to the drawing procedure, but when I disable the timer only the last coordinates are available. It seems to destroy the values of the variables when terminated.

I used a global array to save the mouse coordinates in, and still when the timer is disabled, the array does not contain the mousevalues displayed from the array while the timer is enabled. How do I keep the array values after the timer is disabled?

SOLUTION

Member_2_248744

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ASKER CERTIFIED SOLUTION

Member_2_248744

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Member_2_248744

I forgot this

private
{ Private declarations }
DrawNum: Integer;
aryPoints: Array of T2Points;