Transparent graphics are used everywhere these days. Half the UIs you will have used today will have made some use of composited graphics, overlays, or something similar. You've probably seen:
This is part 1 of a short series that examines alpha-aware graphics using native GDI only - not GDI+, not DirectX, and not with any other custom non-GDI graphics implementation. By the end of the series I will have introduced a small alpha-aware canvas class that you can use to draw standard shapes (rectangles, ellipses, etc) just as you can with the normal TCanvas (and using standard TFont, TPen and TBrush objects), to compose several layers of alpha blended graphics together, and to draw on glass on Vista and Windows 7.
This is a screenshot of the demo program which I used to test this class. It's not the prettiest demo program ever, but you can see all of the above in action in this screenshot:
- Selections with transparent rectangles or other shapes
- Text with a transparent shape behind it, so you can see the through to the background and still clearly read the text
- Custom drawing on glass, such as text with the blurred white background and custom controls
This is part 1 of a short series that examines alpha-aware graphics using native GDI only - not GDI+, not DirectX, and not with any other custom non-GDI graphics implementation. By the end of the series I will have introduced a small alpha-aware canvas class that you can use to draw standard shapes (rectangles, ellipses, etc) just as you can with the normal TCanvas (and using standard TFont, TPen and TBrush objects), to compose several layers of alpha blended graphics together, and to draw on glass on Vista and Windows 7.
This is a screenshot of the demo program which I used to test this class. It's not the prettiest demo program ever, but you can see all of the above in action in this screenshot:
