TftBmpMemIndexOver()

Library Description ›› Memory ››
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Syntax

TftBmpMemIndexOver(wFileIndex As wTftLibParameter1, wX_Pos As wTftLibParameter2, wY_Pos As wTftLibParameter3, bTransparent As bTftLibParameter1, wAlphaColor As wTftLibParameter4, bInvert As bTftLibParameter2, bOverlay As bTftLibParameter3), Byte

Overview

Renders a BMP image stored in FLASH memory by file index and applies optional transparency, color inversion, and pixel-overlay effects.

Parameters

Parameter

Description

wFileIndex

Zero-based BMP file index in FLASH memory.

wX_Pos

X-coordinate of the image’s lower-left corner.

wY_Pos

Y-coordinate of the image’s lower-left corner.

bTransparent

Transparency mode:
0 – Normal (no transparency)
1 – Transparent (skip pixels matching the alpha color)

wAlphaColor

Alpha-key color used when transparency is enabled.

bInvert

Color inversion:
0 – Normal colors
1 – Invert all image colors

bOverlay

Pixel overlay/blending mode:
0 = NONE – No overlay; direct pixel write
1 = OR – Lightens overlaps by setting bits
2 = AND – Keeps only intersecting bits
3 = XOR – Highlights differences / toggles mismatches
4 = NAND – Inverts the AND result; bright overlap
5 = NOR – Inverts the OR result; dark overlay
6 = XNOR – Keeps pixels where both match
7 = ADD – Adds RGB values; brightens overlaps
8 = SUB – Subtracts RGB values; darkens overlaps
9 = AVG – Averages RGB values; soft blend
10 = SCR – Screen-style blend (inverse multiply); bright highlights
11 = MUL – Multiply blend; darker result (similar to Photoshop Multiply)
12 = CON – Contrast mix; enhances midtones non-linearly

Return value

Value

Meaning

0

Operation completed successfully

1

Origin point lies outside the visible display area

2

BMP has zero width or height

4

BMP partially printed outside visible area

Notes

Processing order: transparency check → color inversion → overlay → draw.

Transparent mode is slower because each pixel must be evaluated individually.

Overlay modes are also slower because they require reading and writing each destination pixel.

If global TftPixelCheck is enabled then images partially outside the view area are skipped.

For fastest rendering with no effects, use TftBmpFromMemIndex() instead.

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