Search found 4 matches

by arekay
Mon Jun 06, 2022 1:50 pm
Forum: VCL
Topic: Saving and re-using internal bitmap
Replies: 6
Views: 4705

Re: Saving and re-using internal bitmap

Thank you for your answer; it is very helpful. To make the bitmap work with transparency, it turns out the draw command needs to be: Chart1->Canvas->ReferenceCanvas->Draw(Chart1->ChartRect.Left, Chart1->ChartRect.Top, backChart); In other words, you need to use the ReferenceCanvas, as TTeeCanvas doe...
by arekay
Tue May 24, 2022 12:58 am
Forum: VCL
Topic: Saving and re-using internal bitmap
Replies: 6
Views: 4705

Re: Saving and re-using internal bitmap

Hello: Yes, I'm aware that drawing a million lines is always slow. But, when my application needs it, it needs it. The link you provided does not present any solutions I can identify; I can't see anything about reducing the number of lines to draw. To be clear, I am OK with being slow drawing a mill...
by arekay
Wed May 18, 2022 3:05 am
Forum: VCL
Topic: Saving and re-using internal bitmap
Replies: 6
Views: 4705

Re: Saving and re-using internal bitmap

Hello, Thanks for your answer. Here is a project (in C++ Builder 11 Update 1) that demonstrates the various aspects of my question. By shift-clicking on the chart, you can move the non-zero point, and cause the chart to redraw. The drop-down list controls how many background lines are drawn. At one ...
by arekay
Sat Apr 30, 2022 11:32 pm
Forum: VCL
Topic: Saving and re-using internal bitmap
Replies: 6
Views: 4705

Saving and re-using internal bitmap

I have an application where I use BeforeDrawSeries to draw lines manually (e.g., with MoveTo and LineTo) prior to regular rendering. When there are just tens or hundreds of lines, it works fine, but when there are thousands, it gets bogged down, and so I would like to improve its efficiency. In addi...