add 4bit image support, tools and examples

Tools/Images/README.txt

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+
+bmp2array4bit.py creates C (or C++) code that contains two arrays for adding images to four-bit sprites.  See Sprite_image_4bit for an example.
+
+It is loosely based on Spark Fun's bmp2array script.
+
+You'll need python 3.6 (the original use Python 2.7)
+
+usage: python bmp2array4bit.py [-v] star.bmp [-o myfile.c]
+
+Create the bmp file in Gimp from any image by:
+
+. Remove the alpha channel (if it has one)
+        Layer -> Transparency -> Remove Alpha Channel
+. Set the mode to indexed.
+        Image -> Mode -> Indexed...
+. Select Generate optimum palette with 16 colors (max)
+. Export the file with a .bmp extension. Do NOT select options:
+    . Run-Length Encoded
+    . Compatibility Options: "Do not write color space information" 
+    . There are no Advanced Options available with these settings
+
+I don't have photoshop so cannot help you with that.
+
+The first array produced is the palette for the image.
+The second is the image itself.

Tools/Images/bmp2array4bit.py

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+'''
+
+    This script takes in a bitmap and outputs a text file that is a
+    byte array used in Arduino files.
+
+    It is loosely based on Spark Fun's bmp2array script.
+
+    You'll need python 3.6 (the original use Python 2.7)
+
+    usage: python fourbitbmp2array.py [-v] star.bmp [-o myfile.c]
+    
+    Create the bmp file in Gimp by :
+
+    . Remove the alpha channel (if it has one) Layer -> Transparency -> Remove Alpha Channel
+    . Set the mode to indexed.  Image -> Mode -> Indexed...
+    . Select Generate optimum palette with 16 colors (max)
+    . Export the file with a .bmp extension. Options are:
+        . Run-Length Encoded: not selected
+        . Compatibility Options: "Do not write color space information" not selected
+        . There are no Advanced Options available with these settings
+
+
+    
+
+'''
+
+import sys
+import struct
+import math
+import argparse
+import os
+
+debug = None
+
+def debugOut(s):
+    if debug:
+        print(s)
+
+# look at arguments
+parser = argparse.ArgumentParser(description="Convert bmp file to C array")
+parser.add_argument("-v", "--verbose", help="debug output", action="store_true")
+parser.add_argument("input", help="input file name")
+parser.add_argument("-o", "--output", help="output file name")
+args = parser.parse_args()
+
+if not os.path.exists(args.input):
+    parser.print_help()
+    print("The input file {} does not exist".format(args.input))
+    sys.exit(1)
+
+if args.output == None:
+    output = os.path.basename(args.input).replace(".bmp", ".c")
+else:
+    output = args.output
+
+debug = args.verbose
+
+try:
+    #Open our input file which is defined by the first commandline argument
+    #then dump it into a list of bytes
+    infile = open(args.input,"rb") #b is for binary
+    contents = bytearray(infile.read())
+    infile.close()
+except:
+    print("could not read input file {}".format(args.input))
+    sys.exit(1)
+
+# first two bytes should be "BM"
+upto = 2
+#Get the size of this image
+data = struct.pack("BBBB", contents[upto], contents[upto+1], contents[upto+2], contents[upto+3])
+fileSize = struct.unpack("I", bytearray(data))
+
+upto += 4
+# four bytes are reserved
+
+upto += 4
+
+debugOut("Size of file: {}".format(fileSize[0]))
+
+#Get the header offset amount
+data = struct.pack("BBBB", contents[upto], contents[upto+1], contents[upto+2], contents[upto+3])
+offset = struct.unpack("I", bytearray(data))
+
+debugOut("Offset: {}".format(offset[0]))
+upto += 4
+
+data = struct.pack("BBBB", contents[upto], contents[upto+1], contents[upto+2], contents[upto+3])
+headersize = struct.unpack("I", bytearray(data))
+headerLength = headersize[0]
+startOfDefinitions = headerLength + upto
+debugOut("header size: {}, up to {}, startOfDefinitions {}".format(headersize[0], upto, startOfDefinitions))
+upto += 4
+
+data = struct.pack("BBBB", contents[upto], contents[upto+1], contents[upto+2], contents[upto+3])
+t = struct.unpack("I", bytearray(data))
+debugOut("width: {}".format(t[0]))
+width = t[0]
+
+upto += 4
+data = struct.pack("BBBB", contents[upto], contents[upto+1], contents[upto+2], contents[upto+3])
+t = struct.unpack("I", bytearray(data))
+debugOut("height: {}".format(t[0]))
+height = t[0]
+
+# 26
+upto += 4
+
+data = struct.pack("BB", contents[upto], contents[upto+1])
+t = struct.unpack("H", bytearray(data))
+debugOut("planes: {}".format(t[0]))
+
+upto = upto + 2
+data = struct.pack("BB", contents[upto], contents[upto+1])
+t = struct.unpack("H", bytearray(data))
+debugOut("bits per pixel: {}".format(t[0]))
+bitsPerPixel = t[0]
+
+upto = upto + 2
+data = struct.pack("BBBB", contents[upto], contents[upto+1], contents[upto+2], contents[upto+3])
+t = struct.unpack("I", bytearray(data))
+debugOut("biCompression: {}".format(t[0]))
+
+upto = upto + 4
+data = struct.pack("BBBB", contents[upto], contents[upto+1], contents[upto+2], contents[upto+3])
+t = struct.unpack("I", bytearray(data))
+debugOut("biSizeImage: {}".format(t[0]))
+
+upto = upto + 4
+data = struct.pack("BBBB", contents[upto], contents[upto+1], contents[upto+2], contents[upto+3])
+t = struct.unpack("I", bytearray(data))
+debugOut("biXPelsPerMeter: {}".format(t[0]))
+
+upto = upto + 4
+data = struct.pack("BBBB", contents[upto], contents[upto+1], contents[upto+2], contents[upto+3])
+t = struct.unpack("I", bytearray(data))
+debugOut("biYPelsPerMeter: {}".format(t[0]))
+
+upto = upto + 4
+data = struct.pack("BBBB", contents[upto], contents[upto+1], contents[upto+2], contents[upto+3])
+t = struct.unpack("I", bytearray(data))
+debugOut("biClrUsed: {}".format(t[0]))
+colorsUsed = t
+
+upto = upto + 4
+data = struct.pack("BBBB", contents[upto], contents[upto+1], contents[upto+2], contents[upto+3])
+t = struct.unpack("I", bytearray(data))
+debugOut("biClrImportant: {}".format(t[0]))
+
+upto += 4
+
+debugOut("Upto: {} Number of colors used: {} definitions start at: {}".format(upto, colorsUsed[0],  startOfDefinitions))
+
+#Create color definition array and init the array of color values
+colorIndex = [] #(colorsUsed[0])
+for i in range(colorsUsed[0]):
+    colorIndex.append(0)
+
+#Assign the colors to the array.  upto = 54
+# startOfDefinitions = upto
+for i in range(colorsUsed[0]):
+    upto =  startOfDefinitions + (i * 4)
+    blue = contents[upto]
+    green = contents[upto + 1]
+    red = contents[upto + 2]
+    # ignore the alpha channel.
+
+    # data = struct.pack("BBBB", contents[upto], contents[upto+1], contents[upto+2], contents[upto+3])
+    # t = struct.unpack("I", bytearray(data))
+    # colorIndex[i] = t[0]
+
+    colorIndex[i] = (((red & 0xf8)<<8) + ((green & 0xfc)<<3)+(blue>>3))
+    debugOut("color at index {0} is {1:04x}, (r,g,b,a) = ({2:02x}, {3:02x}, {4:02x}, {5:02x})".format(i,  colorIndex[i], red, green, blue, contents[upto+3]))
+
+#debugOut(the color definitions
+# for i in range(colorsUsed[0]):    
+#     print hex(colorIndex[i])
+
+# perfect, except upside down.
+
+#Make a string to hold the output of our script
+arraySize = (len(contents) - offset[0]) 
+outputString = "/* This was generated using a script based on the SparkFun BMPtoArray python script" + '\n'
+outputString += " See https://github.com/sparkfun/BMPtoArray for more info */" + '\n\n'
+outputString += "static const uint16_t palette[" + str(colorsUsed[0]) + "] = {";
+for i in range(colorsUsed[0]): 
+    # print hexlify(colorIndex[i])
+    if i % 4 == 0:
+        outputString += "\n\t"
+    outputString += "0x{:04x}, ".format(colorIndex[i])
+
+outputString = outputString[:-2]
+outputString += "\n};\n\n"
+outputString += "// width is " + str(width) + ", height is " + str(height) + "\n"
+outputString += "static const uint8_t myGraphic[" + str(arraySize) + "] PROGMEM = {" + '\n'
+
+if bitsPerPixel != 4:
+    print("Expected 4 bits per pixel; found {}".format(bitsPerPixel))
+    sys.exit(1)
+    
+#Start converting spots to values
+#Start at the offset and go to the end of the file
+dropLastNumber = True #(width % 4) == 2 or (width % 4) == 1
+paddedWidth = int(math.ceil(bitsPerPixel * width / 32.0) * 4)
+debugOut("array range is {} {} len(contents) is {} paddedWidth is {} width is {}".format(offset[0], fileSize[0], len(contents), paddedWidth, width))
+
+r = 0
+width = int(width / 2)
+#for i in range(offset[0], fileSize[0]):                 # close but image is upside down.  Each row is correct but need to swap columns.
+#for i in range(fileSize[0], offset[0], -1):
+
+for col in range(height-1, -1, -1):
+    i = 0
+    for row in range(width):
+        colorCode1 = contents[row + col*paddedWidth + offset[0]]  
+
+        if r > 0 and r % width == 0:
+            i = 0
+            outputString += '\n\n'
+        elif (i + 1) % 12 == 0 :
+            outputString += '\n'
+            i = 0
+        
+        #debugOut("cell ({0}, {1})".format(row, col)
+
+        r = r + 1
+        i = i + 1
+        outputString += "0x{:02x}, ".format(colorCode1)
+
+
+    
+#Once we've reached the end of our input string, pull the last two
+#characters off (the last comma and space) since we don't need
+#them. Top it off with a closing bracket and a semicolon.
+outputString = outputString[:-2]
+outputString += "};"
+
+try:
+    #Write the output string to our output file
+    outfile = open(output, "w")
+    outfile.write(outputString)
+    outfile.close()
+except:
+    print("could not write output to file {}".format(output))
+    sys.exit(1)
+
+debugOut("{} complete".format(output))
+debugOut("Copy and paste this array into a image.h or other header file")
+
+if not debug:
+    print("Completed; the output is in {}".format(output))

examples/Sprite/Sprite_image_4bit/Sprite_image.ino

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+/*
+
+  Sketch to show how a Sprite can use a four-bit image with
+  a palette to change the appearance of an image while rendering
+  it only once.
+
+  Example for library:
+  https://github.com/Bodmer/TFT_eSPI
+
+  A Sprite is notionally an invisible graphics screen that is
+  kept in the processors RAM. Graphics can be drawn into the
+  Sprite just as it can be drawn directly to the screen. Once
+  the Sprite is completed it can be plotted onto the screen in
+  any position. If there is sufficient RAM then the Sprite can
+  be the same size as the screen and used as a frame buffer.
+
+  A 16 bit Sprite occupies (2 * width * height) bytes in RAM.
+
+  On a ESP8266 Sprite sizes up to 126 x 160 can be accomodated,
+  this size requires 40kBytes of RAM for a 16 bit color depth.
+  
+  When 8 bit color depth sprites are created they occupy
+  (width * height) bytes in RAM, so larger sprites can be
+  created, or the RAM required is halved.
+
+*/
+
+
+// Set delay after plotting the sprite
+#define DELAY 30
+
+// Width and height of sprite
+#define WIDTH  164
+#define HEIGHT 164
+
+#include "sample_images.h"
+
+TFT_eSPI    tft = TFT_eSPI();         // Declare object "tft"
+
+TFT_eSprite spr = TFT_eSprite(&tft);  // Declare Sprite object "spr" with pointer to "tft" object
+
+const int freq = 5000;
+int screenBrightnessChannel = 0;
+int resolution = 8;
+
+byte red = 31; // Red is the top 5 bits of a 16 bit colour value
+byte green = 0;// Green is the middle 6 bits
+byte blue = 0; // Blue is the bottom 5 bits
+byte state = 0;
+
+int rloop = 0;
+int incr = 1;
+
+uint16_t cmap[16];
+
+void setup()
+{
+  pinMode(21, OUTPUT);
+  ledcSetup(screenBrightnessChannel, freq, resolution);
+  ledcAttachPin(21, screenBrightnessChannel);
+  ledcWrite(screenBrightnessChannel, 127);
+
+  Serial.begin(9600);
+  Serial.println();
+
+  delay(50);
+
+  // Initialise the TFT registers
+  tft.init();
+  
+  spr.setColorDepth(4);
+
+  // Create a sprite of defined size
+  spr.createSprite(WIDTH, HEIGHT);
+
+  // Clear the TFT screen to black
+  tft.fillScreen(TFT_BLACK);
+  
+  // push the image - only need to do this once.
+  spr.pushImage(2, 2, 160, 160, (uint16_t *)stars);
+
+  for (int i = 0; i < 16; i++)
+    cmap[i] = rainbow();
+}
+
+void loop(void)
+{
+  // create a palette with the defined colors and push it.  
+  spr.createPalette(cmap, 16);
+  spr.pushSprite(tft.width() / 2 - WIDTH / 2, tft.height() / 2 - HEIGHT / 2);
+  
+  // update the colors
+  for (int i = 0; i < 15; i++) {
+    cmap[i] = cmap[i + 1];
+  }
+  if (incr == 2) {
+    (void)rainbow();  // skip alternate steps
+  }
+  cmap[15] = rainbow();
+  rloop += incr;
+  if (rloop > 0xc0) {
+    incr = incr == 2 ? 1 : 2;
+    Serial.printf("incr %d, rloop %d\r\n", incr, rloop);
+    rloop = 0;
+    
+  }
+  delay(DELAY);
+
+}
+
+// #########################################################################
+// Return a 16 bit rainbow colour
+// #########################################################################
+unsigned int rainbow()
+{
+    switch (state) {
+      case 0:
+        green ++;
+        if (green == 64) {
+          green = 63;
+          state = 1;
+        }
+        break;
+      case 1:
+        red--;
+        if (red == 255) {
+          red = 0;
+          state = 2;
+        }
+        break;
+      case 2:
+        blue ++;
+        if (blue == 32) {
+          blue = 31;
+          state = 3;
+        }
+        break;
+      case 3:
+        green --;
+        if (green == 255) {
+          green = 0;
+          state = 4;
+        }
+        break;
+      case 4:
+        red ++;
+        if (red == 32) {
+          red = 31;
+          state = 5;
+        }
+        break;
+      case 5:
+        blue --;
+        if (blue == 255) {
+          blue = 0;
+          state = 0;
+        }
+        break;
+    }
+    return red << 11 | green << 5 | blue;
+}
+

examples/Sprite/Sprite_image_4bit/Sprite_image_4bit.ino

@@ -0,0 +1,162 @@
+/*
+
+  Sketch to show how a Sprite can use a four-bit image with
+  a palette to change the appearance of an image while rendering
+  it only once.
+
+  Example for library:
+  https://github.com/Bodmer/TFT_eSPI
+
+  A Sprite is notionally an invisible graphics screen that is
+  kept in the processors RAM. Graphics can be drawn into the
+  Sprite just as it can be drawn directly to the screen. Once
+  the Sprite is completed it can be plotted onto the screen in
+  any position. If there is sufficient RAM then the Sprite can
+  be the same size as the screen and used as a frame buffer.
+
+  A 16 bit Sprite occupies (2 * width * height) bytes in RAM.
+
+  On a ESP8266 Sprite sizes up to 126 x 160 can be accomodated,
+  this size requires 40kBytes of RAM for a 16 bit color depth.
+  
+  When 8 bit color depth sprites are created they occupy
+  (width * height) bytes in RAM, so larger sprites can be
+  created, or the RAM required is halved.
+
+*/
+
+
+// Set delay after plotting the sprite
+#define DELAY 30
+
+// Width and height of sprite
+#define WIDTH  164
+#define HEIGHT 164
+
+#include "sample_images.h"
+
+TFT_eSPI    tft = TFT_eSPI();         // Declare object "tft"
+
+TFT_eSprite spr = TFT_eSprite(&tft);  // Declare Sprite object "spr" with pointer to "tft" object
+
+const int freq = 5000;
+int screenBrightnessChannel = 0;
+int resolution = 8;
+
+byte red = 31; // Red is the top 5 bits of a 16 bit colour value
+byte green = 0;// Green is the middle 6 bits
+byte blue = 0; // Blue is the bottom 5 bits
+byte state = 0;
+
+int rloop = 0;
+int incr = 1;
+
+uint16_t cmap[16];
+
+void setup()
+{
+  pinMode(21, OUTPUT);
+  ledcSetup(screenBrightnessChannel, freq, resolution);
+  ledcAttachPin(21, screenBrightnessChannel);
+  ledcWrite(screenBrightnessChannel, 127);
+
+  Serial.begin(9600);
+  Serial.println();
+
+  delay(50);
+
+  // Initialise the TFT registers
+  tft.init();
+  
+  spr.setColorDepth(4);
+
+  // Create a sprite of defined size
+  spr.createSprite(WIDTH, HEIGHT);
+
+  // Clear the TFT screen to black
+  tft.fillScreen(TFT_BLACK);
+  
+  // push the image - only need to do this once.
+  spr.pushImage(2, 2, 160, 160, (uint16_t *)stars);
+
+  for (int i = 0; i < 16; i++)
+    cmap[i] = rainbow();
+}
+
+void loop(void)
+{
+  // create a palette with the defined colors and push it.  
+  spr.createPalette(cmap, 16);
+  spr.pushSprite(tft.width() / 2 - WIDTH / 2, tft.height() / 2 - HEIGHT / 2);
+  
+  // update the colors
+  for (int i = 0; i < 15; i++) {
+    cmap[i] = cmap[i + 1];
+  }
+  if (incr == 2) {
+    (void)rainbow();  // skip alternate steps
+  }
+  cmap[15] = rainbow();
+  rloop += incr;
+  if (rloop > 0xc0) {
+    incr = incr == 2 ? 1 : 2;
+    Serial.printf("incr %d, rloop %d\r\n", incr, rloop);
+    rloop = 0;
+    
+  }
+  delay(DELAY);
+
+}
+
+// #########################################################################
+// Return a 16 bit rainbow colour
+// #########################################################################
+unsigned int rainbow()
+{
+    switch (state) {
+      case 0:
+        green ++;
+        if (green == 64) {
+          green = 63;
+          state = 1;
+        }
+        break;
+      case 1:
+        red--;
+        if (red == 255) {
+          red = 0;
+          state = 2;
+        }
+        break;
+      case 2:
+        blue ++;
+        if (blue == 32) {
+          blue = 31;
+          state = 3;
+        }
+        break;
+      case 3:
+        green --;
+        if (green == 255) {
+          green = 0;
+          state = 4;
+        }
+        break;
+      case 4:
+        red ++;
+        if (red == 32) {
+          red = 31;
+          state = 5;
+        }
+        break;
+      case 5:
+        blue --;
+        if (blue == 255) {
+          blue = 0;
+          state = 0;
+        }
+        break;
+    }
+    return red << 11 | green << 5 | blue;
+}
+

examples/Sprite/Sprite_image_4bit/sample_images.h

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+#include <TFT_eSPI.h>                 // Include the graphics library (this includes the sprite functions)
+
+extern const uint8_t stars[12800] PROGMEM ;