Scroll Left to Right

[malltinaa]

Hi, Thanks for sharing this library. I use the MarqueeText.ino example. How do I scroll from left to right. (I use Arabic.) I made a few changes but I didn't succeed.

Thanks.

[bartoszbielawski]

Hi,

This example has been created by one of the contributors and they basically created all the logic with right-to-left in mind. The complex solution is to try to invert all the loops (drawing characters, drawing on the display). The simple solution is to invert the whole display in x axis, then pixel column 0 will be on the right. To invert the display pass INVERT_DISPLAY_X in the constructor of the object: https://github.com/bartoszbielawski/LEDMatrixDriver/blob/master/examples/MarqueeText/MarqueeText.ino#L15 Use: LEDMatrixDriver lmd(LEDMATRIX_SEGMENTS, LEDMATRIX_CS_PIN, INVERT_DISPLAY_X); Of course latin letters will be inverted but I guess you need to provide your own letters anyway. Let me know if this helped. Bartosz

[malltinaa]

Thanks for the quick reply But I get the following error:

MarqueeText: 15: 59: error: 'INVERT_DISPLAY_X' was not declared in this scope
 LEDMatrixDriver lmd (LEDMATRIX_SEGMENTS, LEDMATRIX_CS_PIN, INVERT_DISPLAY_X);
                                                                                                              ^
exit status 1
'INVERT_DISPLAY_X' was not declared in this scope

[bartoszbielawski]

My bad. I forgot the constant lives in the class. Try this:

LEDMatrixDriver lmd (LEDMATRIX_SEGMENTS, LEDMATRIX_CS_PIN, LEDMatrixDriver::INVERT_DISPLAY_X);

[malltinaa]

My bad. I forgot the constant lives in the class. Try this:

LEDMatrixDriver lmd (LEDMATRIX_SEGMENTS, LEDMATRIX_CS_PIN, LEDMatrixDriver::INVERT_DISPLAY_X);

I tested. Unfortunately this method does not work.

[bartoszbielawski]

Well, if you can tell me what doesn't work I can suggest a solution. You can always write your own code from scratch. The library doesn't really care about texts, it cares only about pixels.

[malltinaa]

Well, if you can tell me what doesn't work I can suggest a solution. You can always write your own code from scratch. The library doesn't really care about texts, it cares only about pixels.

Thanks Bartosz, I used the original code. According to you, I made the following change to the code and output was the same as the video below: LEDMatrixDriver lmd (LEDMATRIX_SEGMENTS, LEDMATRIX_CS_PIN, LEDMatrixDriver::INVERT_DISPLAY_X);

Demo

[bartoszbielawski]

I'm sorry for late replies, for some reason I get no notifications. Also the vimeo link doesn't work... If I find time I may try myself at home later today.

[malltinaa]

I'm sorry for late replies, for some reason I get no notifications. Also the vimeo link doesn't work... If I find time I may try myself at home later today.

Thanks, I changed the video link.

[bartoszbielawski]

Ah, I see the problem. Now segments are inverted as well. Try this one: LEDMatrixDriver lmd (LEDMATRIX_SEGMENTS, LEDMATRIX_CS_PIN, LEDMatrixDriver::INVERT_DISPLAY_X | LEDMatrixDriver::INVERT_SEGMENT_X);

And let me know if it helped.

[bartoszbielawski]

You can also try to modify this example: https://github.com/bartoszbielawski/LEDMatrixDriver/blob/master/examples/AFGFXMarquee/AFGFXMarquee.ino

It uses a different approach. First it renders text into a buffer and then only copies it to the display. It may be that making this one work needs only inverting a counter or two.

[idreamsi]

I solved the problem. Replace lines 110 to 112 with the following code:

  #ifdef L2R
  //Scroll left to right
    if( ++x > LEDMATRIX_WIDTH ){
    x = -len*8;
    }
  #endif
  #ifdef R2L
  //Scroll right to left
    // Advance to next coordinate
  if( --x < len * -8 ) {
    x = LEDMATRIX_WIDTH;
  }
  #endif 

Only un-comment one of the lines below. (Insert these lines at the beginning of the code.)

#define L2R
//#define R2L

[bartoszbielawski]

Would you care to make a pull request with your changes? Some other people could benefit from the improved example.

[idreamsi]

Would you care to make a pull request with your changes? Some other people could benefit from the improved example.

I will do.

[bartoszbielawski]

Thank you. Can I close the issue or do you have more questions?