SptBmpOverSpt()

SptBmpOverSpt(dwBmpAlias As dwTftLibParameter1, bBuffer As bTftLibParameter1, wOriginX As wTftLibParameter1, wOriginY As wTftLibParameter2, bTransparent As bTftLibParameter2, wAlphaColor As wTftLibParameter3, bInvert As bTftLibParameter3, bOverlay As bTftLibParameter4), Byte

Print an image from program memory merging it on the fly with a sprite buffer as background of the same size to the TFT screen with optional image processing effects.

- If transparent mode is enabled, any pixels matching the specified Alpha Color are omitted, thereby preserving the existing pixels already present in the sprite buffer.

- If an overlay function is selected, it is applied in accordance with the transparency rule.

dwBmpAlias   = Name of the BMP image table stored in flash memory

bBuffer      = Sprite buffer index the image data will be merged with

wOriginX     = X coordinate of the bottom-left corner on the screen where the image will be drawn

wOriginY     = Y coordinate of the bottom-left corner on the screen where the image will be drawn

bTransparent

0 = Normal load (no transparency)

1 = Transparent load (pixels matching the alpha color are skipped)

wAlphaColor = Alpha color value used when transparent loading is enabled

bInvert      

0 = Normal colors

1 = Invert image colors

bOverlay = Pixel overlay effect to apply during the load operation:

0 = NONE – No overlay; direct pixel replacement

1 = OR – Lightens overlapping areas (adds bits); merges bright regions

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

3 = XOR – Highlights differences; toggles pixels where colors differ

4 = NAND – Inverts the intersection; brightens overlap zones

5 = NOR – Inverts the union; creates darker overlays

6 = XNOR – Keeps pixels unchanged where both match; strong masking effect

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

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

9 = AVG – Averages colors; produces a 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 with a non-linear mix

Result:

0 – Operation completed successfully

1 – Invalid buffer index

2 – Buffer size is different from the image to be merged with

3 - Invalid BMP size

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