TftOverlayAreaRect()

TftOverlayAreaRect(wOriginX As wTftLibParameter1, wOriginY As wTftLibParameter2, wAreaWidth As wTftLibParameter3, wAreaHeight As wTftLibParameter4, bOverlay As bTftLibParameter1, wOverlayColor As wTftLibParameter5)

Apply pixel overlay processing using a specified overlay color within a defined rectangular area on the TFT screen.

Parameters:

wOriginX – X coordinate of the bottom-left corner of the overlay area

wOriginY – Y coordinate of the bottom-left corner of the overlay area

wAreaWidth – Width of the region to which the overlay is applied

wAreaHeight – Height of the region to which the overlay is applied

bOverlay – Pixel overlay effect to apply:

0 = NONE – No overlay; direct pixel replacement

1 = OR – Lightens overlapping areas by combining bits; merges bright regions

2 = AND – Keeps only common bits; intersection-style effect

3 = XOR – Highlights differences by toggling differing pixels

4 = NAND – Inverts the intersection; brightens overlap zones

5 = NOR – Inverts the union; produces darker overlays

6 = XNOR – Preserves pixels where both values match; strong masking effect

7 = ADD – Adds color values; brightens overlapping regions (light addition)

8 = SUB – Subtracts color values; darkens overlapping regions (shadow-like effect)

9 = AVG – Averages source and destination colors; soft blending effect

10 = SCR – Screen blend (inverse multiply); brightens highlights

11 = MUL – Multiply blend; darkens overlapping areas (similar to Photoshop “Multiply”)

12 = CON – Contrast blend; enhances midtones using a non-linear mix

wOverlayColor – Overlay color value used for the selected pixel processing mode

Notes:

The overlay operation is relatively slow, as it requires reading and rewriting each pixel within the target area.

If the global TftPixelCheck flag is enabled, boundary checking is performed:

If the defined area lies completely outside the visible screen, no overlay operation is applied.

If the area is partially outside the screen, it is automatically clipped to the visible boundaries.

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