transpose_4strips()

FASTLED_FORCE_INLINE void fl::transpose_4strips	(	const u8 *const	input[4],
		u8 *	output,
		u16	num_leds,
		u8	bytes_per_led )

Transpose 4 LED strips into parallel bit format.

This function transposes 4 LED strips from standard byte-sequential format to bit-parallel format suitable for 4-way PIO output.

Input: 4 strips, each with num_leds * bytes_per_led bytes Output: num_leds * bytes_per_led * 8 bytes

Parameters

input	Array of 4 pointers to LED strip data
output	Pointer to output buffer
num_leds	Number of LEDs per strip (all strips padded to this length)
bytes_per_led	Number of bytes per LED (3 for RGB, 4 for RGBW, etc.)

Note

All strips must be pre-padded to the same length

Output buffer must be pre-allocated by caller

Upper 4 bits of each output byte are zero

Examples

/home/runner/work/FastLED/FastLED/src/fl/math/transposition.h.

Definition at line 722 of file transposition.h.

              {
    // Process each LED
    for (u16 led = 0; led < num_leds; led++) {
        // Process each byte in the LED
        for (u8 byte_idx = 0; byte_idx < bytes_per_led; byte_idx++) {
            // Collect one byte from each strip for this byte position
            u8 strip_bytes[4];
            for (int strip = 0; strip < 4; strip++) {
                strip_bytes[strip] = input[strip][led * bytes_per_led + byte_idx];
            }
 
            // Transpose: extract each bit position from all 4 strips
            for (int bit = 7; bit >= 0; bit--) {
                u8 output_byte = 0;
                // Pack bits from all 4 strips into lower 4 bits
                for (int strip = 0; strip < 4; strip++) {
                    output_byte |= ((strip_bytes[strip] >> bit) & 1) << strip;
                }
                *output++ = output_byte;
            }
        }
    }
}

References FASTLED_FORCE_INLINE, and FL_NOEXCEPT.

Referenced by transpose_strips().

Here is the caller graph for this function: