Add horizontal flip

[gcstr]

We are working on a project where we need to flip the entire screen. When working with shapes and primitives, it's ok, since it's just a matter of math.

But texts are not ok. It would be nice if the lib could support something like setHFlip and the screen flipped horizontally, something like setRot90, setRot180... but flipping the entire screen.

[olikraus]

You mean, the text should appear mirrored? So to say, readable only with a mirror?

[gcstr]

Exactly. Some wearables, like the one we are prototyping, might require that.

I managed to achieve the result I wanted playing with adafruit's library. C isn't really my main language, so the code I wrote is really simple, but did the trick for now:

void Adafruit_SSD1306::flip(void){
  for (int i=0; i<8; i++) {
    reverse(buffer, SSD1306_LCDWIDTH*i, SSD1306_LCDWIDTH*i+(SSD1306_LCDWIDTH-1));
  }
}

I simply iterate through the buffer reversing the array.

[gcstr]

Actually, I got the starting idea from here:

http://nerdclub-uk.blogspot.com.br/2016/03/adding-flip-function-to-adafruits.html?m=1

But it only rotates the screen, feature already in u8g.

I`d like to contribute to the repo, but as I said, it's not my main language. It's just a feature request. 😀

[olikraus]

you could try to change the value 0x0c8 to 0x0c0 in line 130 of u8g_dev_ssd1306_128x64.c (assumming you have this display)

[gcstr]

Yap, that's my display. I'll try that tonight.

[olikraus]

any success?

[gcstr]

Perfect! It worked. Thank you very much.

[johnny-82]

Hi olikraus! sorry for my English. I need to flip horizontally my old "nokia 5210 lcd". I am using U8GLIB_PCD8544. Can you help me change the code? do I have to edit the file "u8g_dev_pcd8544_84x48.c"?

[olikraus]

what about using setRot180?

[johnny-82]

when I use this library the screen appears reflected horizontally

[olikraus]

ok, I see. What about using u8g2 (which is u8glib version 2). It includes a mirror option should solve the problem.

[johnny-82]

thanks a lot! It work with "U8G2_PCD8544_84X48_F_4W_SW_SPI u8g2(U8G2_MIRROR, /* clock=..." the only "problem" is that this library is a bit too heavy...

[olikraus]

HW SPI might be better

[SteveC00k]

I have a similar issue. The text is mirrored. I used this display setting:

u8g_dev_sbn1661_122x32.c

I altered the lines 54 and 59 to 0x0a and it did not mirror. See gfx below. (NOTE: Images are upside down. Sorry but thats how they uploaded.)

Here is what it looks like with the settings before altering.

Here is what it looks like after altering.

Back of LCD.

[SteveC00k]

Here is the datasheet if anyone needs to see it. https://drive.google.com/open?id=1gbZHPdsXN4bUGbe_5cXVszRSPaIAwO8v

[SteveC00k]

Started to use the ug82 lib. I managed to get it working except half the text is chopped off on one of the examples.

[SteveC00k]

I have it working now. Found out how to get it going using this constructor in the examples. U8G2_SED1520_122X32_1 u8g2(U8G2_MIRROR, 8, 9, 10, 11, 4, 5, 6, 7, /dc=/ A0, /e1=/ A3, /e2=/ A2, / reset=/ U8X8_PIN_NONE); // Set R/W to low!