device-epd/lib/image/image.cpp

#include "image.h"
#include "format/JPEG.h"
#include "format/PNG.h"
#include "display.h"

structImageProcess ImageProcess;

// dithering
uint16_t ditheringBufferSize;
int16_t *ditheringCurRowDelta;
int16_t *ditheringNextRowDelta;

void setupImage()
{
	// create buffer for dithering
	ditheringBufferSize = displayGetWidth() + 1;
	ditheringCurRowDelta = new int16_t[ditheringBufferSize];
	ditheringNextRowDelta = new int16_t[ditheringBufferSize];

	setupImageJPEG();
	//setupImagePNG();
}

void ImageNew(int x, int y, int w, int h, bool dithering)
{
	Serial.printf("ImageNew: x: %d, y: %d, dithering: %d \n", x, y, dithering);

	ImageProcess.x = x;
	ImageProcess.y = y;
	ImageProcess.w = w;
	ImageProcess.h = h;
	ImageProcess.dithering = dithering;

	memset(ditheringCurRowDelta, 0, sizeof(ditheringCurRowDelta[0]) * ditheringBufferSize);
	memset(ditheringNextRowDelta, 0, sizeof(ditheringNextRowDelta[0]) * ditheringBufferSize);
}

void ImageWriteBuffer(uint8_t buff[], size_t c)
{
	// initial detect format
	if (ImageProcess.format == 0)
	{
		if (memcmp(buff, ImageHeaderPNG, sizeof(ImageHeaderPNG) - 1) == 0 && false)
		{
			Serial.println(" image format: PNG");
			ImageProcess.format = 3;

			pngOpenFramebuffer();
		}
		else if (memcmp(buff, ImageHeaderJPEG, sizeof(ImageHeaderJPEG) - 1) == 0)
		{
			Serial.println(" image format: JPEG");
			ImageProcess.format = 4;

			jpegOpenFramebuffer();
		}
		else
		{
			ImageProcess.format = 1;
			Serial.println(" unkown image format. first header are:");
			Serial.println(buff[0]);
			Serial.println(buff[1]);
			Serial.println(buff[2]);
			Serial.println(buff[3]);
			Serial.println(buff[4]);
			Serial.println(buff[5]);
		}
	}

	// write display frame
	switch (ImageProcess.format)
	{
	// PNG
	case 3:
		pngWriteFramebuffer(0, buff, c);
		break;
	// JPEG
	case 4:
		jpegWriteFramebuffer(0, buff, c);
		break;
	}
}

void ImageFlushBuffer()
{
	// update display
	switch (ImageProcess.format)
	{
	// PNG
	case 3:
		pngFlushFramebuffer();
		break;
	// JPEG
	case 4:
		jpegFlushFramebuffer();
		break;
	}

	// clear settings
	ImageProcess.format = 0;
	ImageProcess.x = 0;
	ImageProcess.y = 0;
	ImageProcess.w = 0;
	ImageProcess.h = 0;
	ImageProcess.dithering = false;
}

void ImageProcessPixel(uint16_t x, uint16_t y, uint8_t rgba[4])
{
	uint8_t r = rgba[0]; // 0 - 255
	uint8_t g = rgba[1]; // 0 - 255
	uint8_t b = rgba[2]; // 0 - 255

	int16_t gray = round(r * 0.3 + g * 0.59 + b * 0.11);
	int16_t blackOrWhite;

	// Add errors to color if there are
	if (ImageProcess.dithering)
	{
		gray += ditheringCurRowDelta[x];
	}

	if (gray <= 127)
	{
		blackOrWhite = 0;
	}
	else
	{
		blackOrWhite = 255;
	}

	if (ImageProcess.dithering)
	{
		int16_t oldPixel = gray;
		int16_t newPixel = blackOrWhite;

		int err = oldPixel - newPixel;

		if (x > 0)
		{
			ditheringNextRowDelta[x - 1] += err * 3 / 16;
		}
		ditheringNextRowDelta[x] += err * 5 / 16;
		ditheringNextRowDelta[x + 1] += err * 1 / 16;
		ditheringCurRowDelta[x + 1] += err * 7 / 16;

		if (x == 0 && y > 0)
		{
			// new line
			memcpy(ditheringCurRowDelta, ditheringNextRowDelta, sizeof(ditheringCurRowDelta[0]) * ditheringBufferSize);
			memset(ditheringNextRowDelta, 0, sizeof(ditheringNextRowDelta[0]) * ditheringBufferSize);
		}
	}

	GFXcanvas1 *canvas = displayGetCanvas();
	canvas->drawPixel(ImageProcess.x + x, ImageProcess.y + y, (uint16_t)blackOrWhite);
}