blah blah blah is here! blah blah » Close

0
storm33229
121
241 views

C# Drawing to Bitmap Laggy

up0down
link

I need to find an efficient way to draw basic rectangles to a bitmap and have my PictureBox reflect that bitmap. As it stands I am drawing to the bitmap and my PictureBox reflects that image. However the drawing is super laggy; especially when you jerk the mouse across the canvas.

How can I fix this?

add comment
last answered 2 years ago

1 answers

Sort:
up0down
tick
link

OK, so I fixed the problem by drawing lines and filling in "bad" spots (happened when moving slowly) with circles. Here's the code:

private void PaintPoints()
        {
            try
            {
                for (int i = 1; i < _pointsToDraw.Count; i++)
                {
                    _graphics = Graphics.FromImage(_project.Map.BMP);
                    _graphics.FillEllipse(new SolidBrush(_color), _pointsToDraw[i].X - (_brushSize / 2), _pointsToDraw[i].Y - (_brushSize / 2), _brushSize, _brushSize);
                    _graphics.DrawLine(new Pen(new SolidBrush(_color), _brushSize), _pointsToDraw[i - 1], _pointsToDraw[i]);
                    _graphics.Dispose();
                    canvas.Image = _project.Map.BMP;
                    canvas.Invalidate();
                    _pointsToDraw.RemoveAt(i - 1);
                }
            }
            catch
            {
                PaintPoints();
            }
            finally
            {
                if (!Draw())
                {
                    _pointsToDraw.Clear();
                }
            }
        }

(x)
storm33229
121

I should also mention that multi-threading is being used. Main thread creates points, second thread draws on top of them.

add comment
Feedback