Downloading Fonts

[matt alder]

Hi again,

I'm currently integrating your GLK12232-25 into a new product and I wanted to be able to load fonts into the display from a microcontroller.

I have been following your PCB Rev 2 manual to construct the font header and after much pain in trial and error I think I have found a typo.

In Table 8 you explain the structure of the font header. You say the number of bytes for each character follows the character offset. Well it would appear that instead of putting in the number of bytes, I need to put in the number of columns I want displayed.

Is this the case? If so is the manual or the firmware wrong? I don't want to hardcode one method and then change it if you are going to fix your firmware.

Thanks

Matt

[Jeroen Vonk]

In Table 8 you explain the structure of the font header. You say the number of bytes for each character follows the character offset. Well it would appear that instead of putting in the number of bytes, I need to put in the number of columns I want displayed.

Is this the case? If so is the manual or the firmware wrong? I don't want to hardcode one method and then change it if you are going to fix your firmware.

You are right, it is the width of the actual character, not the total number of bytes. I've written the routine in C#, I don't know if it is usefull for you, but this is the code which I wrote to construct the font data.

Code: Select all

		public byte[] Data
		{
			get
			{
				const byte cHeaderLength=6;
				const byte cPlaceHolder = 0xFF;

				byte[] tmpArr;
				int ix;
				int numbytes;
				int count;
				int offset;
				int chardatalength=0;

				// determine total fontdata
				for (int i=0;i<fontdata.ArrBitmap.Length;i++)
					chardatalength += (int)Math.Ceiling((double)(fontdata.ArrBitmap[i].Width*fontdata.ArrBitmap[i].Height)/8);

				// start of fontdata in array
				offset = cHeaderLength + fontdata.charcount*3;

				// Init array length
				tmpArr = new byte[cHeaderLength+chardatalength+fontdata.ArrBitmap.Length*3];

				// Fill array header
				tmpArr[0] = cPlaceHolder; // placeholder
				tmpArr[1] = cPlaceHolder; // placeholder
				tmpArr[2] = fontdata.width;
				tmpArr[3] = fontdata.height;
				tmpArr[4] = (byte)fontdata.firstchar;
				tmpArr[5] = (byte)(((byte)fontdata.firstchar)+(fontdata.charcount-1));

				// Fill bitmap data
				for (int i=0;i<fontdata.ArrBitmap.Length;i++)
				{
					numbytes = (byte)(Math.Ceiling(((double)(fontdata.ArrBitmap[i].Width * fontdata.ArrBitmap[i].Height))/8));

					count = 0;
					for (int j=0;j<fontdata.ArrBitmap[i].Width;j++) // X
					{
						for (int k=0;k<fontdata.ArrBitmap[i].Height;k++) // Y
						{
							ix = (int)(count/8);

							if(fontdata.ArrBitmap[i].GetPixel(j,k).GetBrightness()>(20/100))
							{
								// tmpArr[ix+offset] = (byte)(tmpArr[ix+offset] + ((byte)(Math.Pow(2,(count % 8)))));
							}
							else
								tmpArr[ix+offset] = (byte)(tmpArr[ix+offset] + ((byte)(Math.Pow(2,(count % 8)))));

							count++;
						}
					}
					
					// Fill header info
					tmpArr[6 + (i*3)]     = (byte)(offset/256);
					tmpArr[6 + (i*3) + 1] = (byte)offset;
					tmpArr[6 + (i*3) + 2] = (byte)fontdata.ArrBitmap[i].Width;

					offset = offset + numbytes;
				}

				return tmpArr;
			}
		}

[matt alder]

Thanks very much, I'm not using C# but it is very helpfull

Matt