From 7a57b2985f567e56d57d0a0229e3a4759797fa31 Mon Sep 17 00:00:00 2001
From: Thomas Ballmann <mail@i-2xdream.de>
Date: Fri, 20 Mar 2020 20:04:41 +0100
Subject: [PATCH] first step for jpeg image dithering #7

---
 include/image.h     |   2 +
 include/imageJPEG.h |  16 +++++++
 src/imageJPEG.cpp   | 114 ++++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 129 insertions(+), 3 deletions(-)
 create mode 100644 include/imageJPEG.h

diff --git a/include/image.h b/include/image.h
index 6e8a847..6e88919 100644
--- a/include/image.h
+++ b/include/image.h
@@ -13,6 +13,8 @@ typedef struct
 	bool dithering;
 } structImageProcess;
 
+void setupImage();
+
 void ImageNew(int x, int y, int w, int h, bool dithering);
 void ImageWriteBuffer(uint8_t buff[], size_t c);
 void ImageFlushBuffer();
diff --git a/include/imageJPEG.h b/include/imageJPEG.h
new file mode 100644
index 0000000..449d0c1
--- /dev/null
+++ b/include/imageJPEG.h
@@ -0,0 +1,16 @@
+#ifndef IMAGE_JPEG_H
+#define IMAGE_JPEG_H
+
+#include "image.h"
+extern structImageProcess ImageProcess;
+
+// @see http://www.libpng.org/pub/png/spec/1.2/PNG-Structure.html
+const char ImageHeaderJPEG[] = "\xFF\xD8\xFF\xE0\x00\x10\x4A\x46\x49\x46\x00";
+// FF E0 00 10 4A 46 , 49 46 00
+
+void setupImageJPEG();
+void jpegOpenFramebuffer();
+void jpegWriteFramebuffer(int offset, uint8_t bitmap[], int c);
+void jpegFlushFramebuffer();
+
+#endif
\ No newline at end of file
diff --git a/src/imageJPEG.cpp b/src/imageJPEG.cpp
index 07aa2ed..214ea38 100644
--- a/src/imageJPEG.cpp
+++ b/src/imageJPEG.cpp
@@ -7,6 +7,14 @@
 File tmpFileBuffer;
 bool tft_output(int16_t x, int16_t y, uint16_t w, uint16_t h, uint16_t *bitmap);
 
+static constexpr int MAX_WIDTH = 640;
+static constexpr uint8_t BLOCK_SIZE = 15;
+static uint8_t blockDelta[BLOCK_SIZE * MAX_WIDTH + 1];
+
+static int16_t curRowDeltaJ[MAX_WIDTH + 1];
+
+unsigned int pixelCount = 0;
+
 void setupImageJPEG()
 {
 	Serial.println("setupJPEG");
@@ -16,6 +24,8 @@ void setupImageJPEG()
 
 	// The decoder must be given the exact name of the rendering function above
 	TJpgDec.setCallback(tft_output);
+
+	memset(blockDelta, 0, sizeof(blockDelta));
 }
 
 void jpegOpenFramebuffer()
@@ -29,11 +39,13 @@ void jpegOpenFramebuffer()
 	{
 		Serial.println("Failed to open file for writing");
 	}
+
+	pixelCount = 0;
 }
 
 void jpegWriteFramebuffer(int offset, uint8_t bitmap[], int c)
 {
-	//Serial.println("jpegWriteFramebuffer");
+	Serial.print(".");
 	if (tmpFileBuffer)
 	{
 		tmpFileBuffer.write(bitmap, c);
@@ -42,21 +54,97 @@ void jpegWriteFramebuffer(int offset, uint8_t bitmap[], int c)
 
 void jpegFlushFramebuffer()
 {
-	//Serial.println("jpegFlushFramebuffer");
 	if (tmpFileBuffer)
 	{
 		tmpFileBuffer.close();
+
+		uint16_t w = 0, h = 0;
+		TJpgDec.getFsJpgSize(&w, &h, "/tmp.jpeg");
+		Serial.print("Image size: ");
+		Serial.print(w);
+		Serial.print("x");
+		Serial.println(h);
 		TJpgDec.drawFsJpg(0, 0, "/tmp.jpeg");
 	}
 }
 
+void draw_XXX(uint32_t x, uint32_t y, uint8_t color)
+{
+	//uint8_t r = ((color >> 11) & 0x1F);
+	//uint8_t g = ((color >> 5) & 0x3F);
+	//uint8_t b = (color & 0x1F);
+	/*
+	uint8_t r = ((((color >> 11) & 0x1F) * 527) + 23) >> 6;
+	uint8_t g = ((((color >> 5) & 0x3F) * 259) + 33) >> 6;
+	uint8_t b = (((color & 0x1F) * 527) + 23) >> 6;
+	*/
+	uint32_t blue = color & 0x001F;	 // 5 bits blue
+	uint32_t green = color & 0x07E0; // 6 bits green
+	uint32_t red = color & 0xF800;	 // 5 bits red
+
+	int16_t gray = round(red * 0.3 + green * 0.59 + blue * 0.11);
+	int16_t blackOrWhite;
+
+	// Add errors to color if there are
+	if (ImageProcess.dithering)
+	{
+		gray += curRowDeltaJ[x];
+	}
+
+	if (gray <= 127)
+	{
+		blackOrWhite = 0;
+	}
+	else
+	{
+		blackOrWhite = 255;
+	}
+
+	displayWritePixel(ImageProcess.x + x, ImageProcess.y + y, blackOrWhite);
+}
+
+void on_drawPixel(uint32_t x, uint32_t y, uint32_t color)
+{
+	pixelCount++;
+
+	uint32_t blockPageY = y - ((y / 16) * 16);
+	blockDelta[(blockPageY * MAX_WIDTH) + x] = color;
+
+	// TODO bessere lösung finden !
+	if (pixelCount == 10240)
+	{
+		// new block
+		uint32_t originOffsetY = ((y / 16) * 16);
+
+		for (uint16_t _y = 0; _y <= BLOCK_SIZE; _y++)
+		{
+			for (uint16_t _x = 0; _x < MAX_WIDTH; _x++)
+			{
+				uint32_t originX = _x;
+				uint32_t originY = originOffsetY + _y + (blockPageY * 16);
+				uint8_t originColor = blockDelta[(_y * MAX_WIDTH) + _x];
+				draw_XXX(originX, originY, originColor);
+			}
+		}
+
+		// clean buffer
+		memset(blockDelta, 0, sizeof(blockDelta));
+
+		pixelCount = 0;
+	}
+}
+
 // This next function will be called during decoding of the jpeg file to
 // render each block to the TFT.  If you use a different TFT library
 // you will need to adapt this function to suit.
 bool tft_output(int16_t x, int16_t y, uint16_t w, uint16_t h, uint16_t *bitmap)
 {
-	if (true)
+	if (false && y == 0)
 	{
+		//tft_output: x = 0 y = 0 w = 16 h = 16
+		//tft_output: x = 16 y = 0 w = 16 h = 16
+		//tft_output: x = 384 y = 0 w = 6 h = 16
+		//tft_output: x = 0 y = 16 w = 16 h = 16
 		Serial.print("tft_output: x = ");
 		Serial.print(x);
 		Serial.print(" y = ");
@@ -69,11 +157,31 @@ bool tft_output(int16_t x, int16_t y, uint16_t w, uint16_t h, uint16_t *bitmap)
 
 	// Stop further decoding as image is running off bottom of screen
 	if (y >= display.height())
+	{
+		Serial.println("y is out of display range!");
 		return 0;
+	}
 
 	// This might work instead if you adapt the sketch to use the Adafruit_GFX library
 	display.drawRGBBitmap(x, y, bitmap, w, h);
 
+	int16_t _y = y;
+	for (int16_t j = 0; j < h; j++, _y++)
+	{
+		for (int16_t i = 0; i < w; i++)
+		{
+			// geht richtig
+			//display.writePixel(x + i, y, bitmap[j * w + i]);
+
+			// geht auch aber letzte zeil fehlt
+			on_drawPixel(x + i, _y, bitmap[j * w + i]);
+		}
+	}
+	if (false && y == 0)
+	{
+		Serial.println(pixelCount);
+	}
+
 	// Return 1 to decode next block
 	return 1;
 }
\ No newline at end of file