the logic after a bitmap to byte array conversion

Can someone explain me the logic of this conversion.

Is there a pattern that you can see when looking at a byte array?

Also, how do you convert a byte array back to an image?

Can you explain the logic of your question?

A monochrome KS0108 stores a byte vertically i,e. 8 pixels per byte. A T6963C stores a byte horizontally.

A full colour TFT might have 16-bit colour per pixel. Normally written in bigendian order.
You can generally write the pixels in any direction.

However, a software library could choose any private storage that it likes.
You just need to comply with the software.

David.

for example :

static uint8_t screenmemory = {
//SparkFun Electronics LOGO

// ROW0, BYTE0 to BYTE63
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xE0, 0xF8, 0xFC, 0xFE, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0x0F, 0x07, 0x07, 0x06, 0x06, 0x00, 0x80, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,

// ROW1, BYTE64 to BYTE127
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x81, 0x07, 0x0F, 0x3F, 0x3F, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xFE, 0xFC, 0xFC, 0xFC, 0xFE, 0xFF, 0xFF, 0xFF, 0xFC, 0xF8, 0xE0,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,

// ROW2, BYTE128 to BYTE191
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFC,
0xFE, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xF1, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xF0, 0xFD, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,

// ROW3, BYTE192 to BYTE255
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x7F, 0x3F, 0x1F, 0x07, 0x01,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,

// ROW4, BYTE256 to BYTE319
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x7F, 0x3F, 0x1F, 0x1F, 0x0F, 0x0F, 0x0F, 0x0F,
0x0F, 0x0F, 0x0F, 0x0F, 0x07, 0x07, 0x07, 0x03, 0x03, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,

// ROW5, BYTE320 to BYTE383
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF,
0x7F, 0x3F, 0x1F, 0x0F, 0x07, 0x03, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

this is the Sparkfun logo

0x00 is probably “LED off”

what about the other data : 0xFF, 0x7F, 0x3F, …

edit : nevermind found an explanation :

http://microview.io/Font/creating-fonts-for-microview.html

Well, it would have been a lot simpler to just quote the model number or post a link to your display.
Ok, we have to guess:

   // ROW0, BYTE0 to BYTE63
   ...
   // ROW5, BYTE320 to BYTE383

It looks like the data is organised as six Rows 0-5. 64 bytes per row. (512 bits)

This will either be 512x6 (width x height) or it will be KS0108 style 64x48.

My money is on KS0108 style. i.e. one byte does 8 vertical pixels. A "ROW" is 8-raster lines.

David.

I'm experimenting with a micro oled from Sparkfun :

Well, there you are. Look at your link. The display is Screen Size: 64x48 pixels (0.66" Across) with a SSD1306 controller.

So you just wire it up according to instructions and use a SSD1306 library.

David.

yeah,

just wanted to know the logic behind these kind of arrays :smiley:

I explained in #3