BufferedGraphics object will AutoScroll position
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Hi guys, I've been working on a custom component which acts as a 'view' control, such that it manually paints cells for child items. The component can contain hundreds of child items, which means that I've had to utilise the
BufferedGraphicsobject for maintaining the graphics, and reset it only when the component is resized or when the child items are changed. Each child items also owns it's ownBufferedGraphicsobject to maintain the rendering of each item (since these items can contain anImagein the graphics, it speeds up the painting considerably.) A problem surfaces when I start to take into account scrolling through the use ofAutoScrollandAutoScrollPosition. I've spent a good while trying to search for an answer to applying the scroll position offset to aBufferedGraphicsand I've yet yielded unsuccessful results. Several problems are standing in the way of the scrolling functionality: 1. Graphics.TranslateTransform() or Graphics.Transform = new Matrix() does not translate a BufferedGraphics.Render() operation. I believe this is namely because the Render() function just paints directly onto theGraphicshandle for the region it was allocated by. For example, the below does not work:override void OnPaint(PaintEventArgs e)
{
// code here which deals with allocating the buffer if it needs creating// translate by the auto scroll position e.Graphics.TranslateTransform(-AutoScrollPosition.X, -AutoScrollPosition.Y); // render the buffered graphics onto the graphics handle for the paint event this.bufferedGraphics.Render(e.Graphics);}
2. Following the code in this example [^] results in many invalidations, which causes the graphics to lag to the point that it's infeasible for the component. My question is, is there a reliable method of being able to translate the buffered graphics of a
BufferedGraphicsobject when painting onto aGraphicshandle? For instance, could I allocate myBufferedGraphicsas I do in point #1, and intrinsically invalidate the component upon scrolling and simply offset the buffered graphics depending on the position the user has scrolled to? If not, can anyone recommend a suitable repla -
Hi guys, I've been working on a custom component which acts as a 'view' control, such that it manually paints cells for child items. The component can contain hundreds of child items, which means that I've had to utilise the
BufferedGraphicsobject for maintaining the graphics, and reset it only when the component is resized or when the child items are changed. Each child items also owns it's ownBufferedGraphicsobject to maintain the rendering of each item (since these items can contain anImagein the graphics, it speeds up the painting considerably.) A problem surfaces when I start to take into account scrolling through the use ofAutoScrollandAutoScrollPosition. I've spent a good while trying to search for an answer to applying the scroll position offset to aBufferedGraphicsand I've yet yielded unsuccessful results. Several problems are standing in the way of the scrolling functionality: 1. Graphics.TranslateTransform() or Graphics.Transform = new Matrix() does not translate a BufferedGraphics.Render() operation. I believe this is namely because the Render() function just paints directly onto theGraphicshandle for the region it was allocated by. For example, the below does not work:override void OnPaint(PaintEventArgs e)
{
// code here which deals with allocating the buffer if it needs creating// translate by the auto scroll position e.Graphics.TranslateTransform(-AutoScrollPosition.X, -AutoScrollPosition.Y); // render the buffered graphics onto the graphics handle for the paint event this.bufferedGraphics.Render(e.Graphics);}
2. Following the code in this example [^] results in many invalidations, which causes the graphics to lag to the point that it's infeasible for the component. My question is, is there a reliable method of being able to translate the buffered graphics of a
BufferedGraphicsobject when painting onto aGraphicshandle? For instance, could I allocate myBufferedGraphicsas I do in point #1, and intrinsically invalidate the component upon scrolling and simply offset the buffered graphics depending on the position the user has scrolled to? If not, can anyone recommend a suitable replaJust for anyone with a similar question in the future, I managed to resolve this quite simply. Upon the OnScroll event method, simply invalidate the
BufferedGraphicsobject by disposing it, and reset it back to null. Invalidate the whole component, and when constructing the newBufferedGraphicsobject, set thetargetRectangleparameter'sXandYvalues to the respectiveAutoScrollPositionvalues. Why this isn't mentioned elsewhere, I don't know.