README.md
December 5, 2022 ยท View on GitHub
Description
Some additions: AlphaBltStrecth and AlphaBlendStretch with and without interpolation (bilinear). Thanks to Ron van Tilburg for the fast 'integer maths' version of Peter Scale's 'Bilinear resizing' routine. And about this, a note: API AlphaBlend stretches using nearest-neighbour method (it only allows COLORONCOLOR for SetStretchBltMode function). This has a simple explanation: interpolation of alpha-bitmaps involves "pre-blending" (composition) alpha-pixels before rendering onto given DC. This complicates processing. This is supposed what GDI+ solves. Attached, there is a GDI+ test project for comparison purposes (compare flower contour-pixels of both tests; increase iterations for better appreciation and use AlphaBlendStretch function).
Update #1. Some effects; packed in mDIB32Ext module: 'ConvertToGrey', 'BlendWithColor' and 'ChangeGlobalAlpha'. You can add your own ones. Remember pixel data is stored as ARGB (BGRA byte array).
More Info
| Submitted On | 2005-05-14 00:00:52 |
| By | Carles P.V. |
| Level | Intermediate |
| User Rating | 5.0 (140 globes from 28 users) |
| Compatibility | VB 6.0 |
| Category | Graphics |
| World | Visual Basic |
| Archive File | Stretching1888045132005.zip |