Extending TFT_eSPI library

[FrankBoesing]

Hi,

i'd like to extend your great library. Some needed functions are "private", so this is not possible. Changing that "private:" into "protected:" would allow to use inheritance and to add extensions on top of your lib.

Is there a chance that you change this?

Thank you in advance, 
Frank

[FrankBoesing]

p.s. and could you add non-inlined versions of begin_tft_write() / end_tft_write(), please?

[Bodmer]

Maybe, a few provisos:

1. The extensions must be published online for Arduino users - explain what is proposed.
2. I suspect not all need to be removed from private - which ones?
3. Code is inline for performance so there would need to be a default inline, not sure how this can be changed in a tidy way without another #define.

[FrankBoesing]

Hi, yes it is intended to publish it /them
A first extension is to add the TTF fonts used by the ILI9341_t3 library ((c) Paul Stoffregen and others). Years ago I converted >900 Google fonts to it: https://github.com/FrankBoesing/fonts/tree/master/ofl - they display pretty fast.

I have uploaded an example here: https://github.com/FrankBoesing/WT32-SC01-TTF-TEST - it includes your library, slightly edited.
At the moment, it only needs begin_tft_write() / end_tft_write() - i've added non-inlined versions.

[Bodmer]

Hi, thanks, that is great.

I have run your example with a few minor tweaks on an RP2040 using the stock library. It runs very well.

I used startWrite() and endWrite() as these are the user interface for private begin_tft_write and end_tft_write. I need to think on this further as there may be a DMA transaction iin progress when the TTF font call is made and this needs to wait. At the moment I think a dedicated start (with DMA wait) and end functions may be needed.

[FrankBoesing]

No hurry, take your time :)
I'll use startWrite() until then.

[FrankBoesing]

I'd like to add some methods to make a nice tool work - I modified it to work with other screen-sizes (than ILI9341). It's a PowerPoint :) with a macro that converts the screens to tft display commands.... you can create your GUI with powerpoint, start the macro and get a (almost) 1:1 sourcecode that displays this gui on the tft...

This is the original: https://github.com/KrisKasprzak/Powerpoint-ILI9341_t3

[Bodmer]

Interesting. Thanks for the link. I patched together Kris's sketch and your example and it works fine apart from the button text since that uses a different font render call. This PowerPoint idea is rather neat, however I could not run the macro, possibly because I have an older version of PowerPoint (2010 !).

[Bodmer]

I have added the option in v2.4.24 to optionally use the "print" method in the button class, so now your extension example correctly plots the font in the button.

Just a simple change is needed to your example code to invoke the behaviour:

  void setTTFFont(const tftfont_t &f)
  {
    font = &f;
    setTextFont(255);
  }

[FrankBoesing]

Thanks :)
Today, I spent some time to work on the Powerpoint makro. It is a pity that it does not work for you!
I'll create a repository, tomorrow, with a new version that support all displays, auto-adjusts the slide-size, better font handling, and optimizes the output (i.e. dont set the color & font if unchanged, and reduce duplicate comments).
I'll upload a first version of my "font extension" lib for your tft_eSPI, too.

[FrankBoesing]

Hm.. however... i just took a look... it seems my version is Powerpoint 2007 (?)

Can you post the errormessages?

[Bodmer]

It just reports that the file is corrupted and cannot be loaded. Maybe I'll download and try again.

[Bodmer]

OK, security blocked the pptm file type - just had to disable the security lock on it - running now.

[FrankBoesing]

Great news :) I'll publish my version tomorrow..

[Bodmer]

OK, great.

I have added filled H/V gradient rectangles for compatibility.

[Bodmer]

Here is my test sketch that runs under the Arduino environment:
PowerPointGUI_2_VB_Test.zip

One thing to fix is to get rid of this warning:

...PowerPointGUI_2_VB_Test.ino:40:76: warning: ISO C++ forbids converting a string constant to 'char*'...

An approach is needed to work out a simple edit the sketch to allow user defined values to be updated on the screen.

[FrankBoesing]

I had added the gradients too... you're too fast for me :) OK, I remove my version from the lib.

An approach is needed to work out a simple edit the sketch to allow user defined values to be updated on the screen.

Yes! But at the moment, I have no good Idea..

[Bodmer]

I had a go at tweaking the macro code myself. I expect you noticed there were a few bugs that needed fixing. TFT_eSPI handles ellipses so there is no need to assume a circle is drawn and I have updated the code. I have created a test slide but it is not complete yet. Here is a copy FWIW.

[FrankBoesing]

Hi, i've uploaded my version.
It generates a .h file now - take a look at the makro. So far, it's not tested much. I found some issues, but I the code is so different that it would be better if you apply the bugfixes yourself and make a pullrequest with your changes :)

https://github.com/FrankBoesing/PowerPointToTFT

[FrankBoesing]

A first version of the library is here:
https://github.com/FrankBoesing/TFT_eSPI_ext

[FrankBoesing]

Hm,, looks like we have to add a scaling to the fonts-sizes, too. They are too small with a 480x320 display.

[Bodmer]

OK. I will have a look at your library later today. At the moment I can see it will not be recognised as an Arduino library as their are some rules to follow. The fonts you have created look good and characters are well formed, I will have to try the Perl script later too.

[Bodmer]

I've been experimenting with a way to signal variables in tables and to generate the appropriate lines of code. Example:

This generates code like this that will need to be editted by the user:

Display.fillRect(65, 103, 61, 29, 65405);
Display.setTextColor(0);
Display.setTTFFont(Arial_8);
Display.setCursor(75, 114 );
static int tab11 = 0;
Display.print(tab11);

Display.fillRect(126, 103, 65, 29, 65405);
Display.setTextColor(0);
Display.setTTFFont(Arial_8);
Display.setCursor(136, 114 );
static float tab21 = 0.00;
Display.print(tab21);

Display.fillRect(191, 103, 68, 29, 65405);
Display.setTextColor(0);
Display.setTTFFont(Arial_8);
Display.setCursor(201, 114 );
const char tab31[] = "Text";
Display.print(tab31);
'''

[FrankBoesing]

I think the font sizes on the slast sliede of kris fit only by chance for the 320*240 ili9341.
I think we may need to convert the sizes to "dot". What do you think, does it make sense?

With 480x320 the fontsize 8 in the "screen2" table is ok, but the headline is way too small and should roughly double the size...

[Bodmer]

Yes, the screen w and h is 1.5x so maybe that is a good scale factor for a 320x480 screen.

[FrankBoesing]

My version calcs the scale factor with the help of screen size and display size to get the "dot"s needed by Powerpoint for all elements und uses the font size the slides uses. However, this using that fontsize seems not to be correct, although PP scales the fonts.... the x1.5 seems not to be correct, too, as it is too less for the headline and too large for the 8pt fonts in the table. Have to think about it...

[Bodmer]

The answer may be to change the page size in PowerPoint as it seems to be custom:

[Bodmer]

I increased the page dimensions manually and the fonts are then automatically scaled for existing pages, but end up at odd values so have to be manually tweaked.

Maybe there is a way to set the page size from the macro?

[Bodmer]

Ah, your macro does change the page size, when I manually change the page size the fonts are scaled. When I run the macro thenit changes the page size but the fonts are not scled down so the page then looks bad on the PC screen...

Tests suggest that the point size produced in the sketch is only 1 point down on a good match for the smaller (<20 size) characters.

[FrankBoesing]

No, headline is 13 but should be ~25 - fontsize in the table is ok.
I think I know the reason. Font sizes are in px - but windows fontsize is "dot".
Will try to fix that tomorrow evening...

[FrankBoesing]

Still doesn't look "perfect", but indeed the 1.5 scalefactor seems almost ok.. have updated the ppt.

[Bodmer]

I am getting a very close match with the following approach.

The problem is that there is a scale factor between the pixel and the font point size so that factor needs to be determined, This is a constant for all screen sizes. I found a scale factor of SF = 1.385 is very close. The page size is then set to say 479/SF and 319/SF. All pixel based coords are then scaled up by SF to bring them back in range (e.g. 0-479 for width). The fonts are then rendered the correct relative size to a graphics box. I also found I had to increase the cursor y position by fontSize/3 to get the text in the box. Now all other slides look good too and strings are very close to being the correct length. Because the fonts are digitised it can never be perfect due to pixel level rounding, especially on small fonts.

Screen (captured with a cheap webcam!)

Master slide:

[Bodmer]

Note those green rectangles are sepatate graphics objects to the text (unfilled rectangles) so their size is in pixels rather than font point size.

[Bodmer]

My latest version 1.0.4 of the sketch generator is here, it includes test slides only at the moment:
https://github.com/Bodmer/PowerPoint_to_sketch

This includes the first attempt at creating boxes with associated variables.

[FrankBoesing]

My latest version 1.0.4 of the sketch generator is here, it includes test slides only at the moment: https://github.com/Bodmer/PowerPoint_to_sketch

This includes the first attempt at creating boxes with associated variables.

The link does not work for me :)

[Bodmer]

Whoops! Made it public, so link should work now.

[FrankBoesing]

Looks good.
It doesn't make much sense for us to work on different versions. It's also difficult to apply your changes each time, and I honestly don't have much desire for this manual effort. I have changed too much.

I'll wait for your version and do other things.
Wish you good luck, and have fun! I look in some time again and take over your version then. Thank you!

Frank

[Bodmer]

Agreed, it does not make much sense to have diverging versions. My version is really just to test ideas and see what works since I have not tried this before or used VB.

I think step 1 should be to focus on the font library extension as that is key to getting the PowerPoint approach working. I will clone your copy of the TFT_ext library and create a list of comments for consideration. OK?

[FrankBoesing]

Agreed, it does not make much sense to have diverging versions. My version is really just to test ideas and see what works since I have not tried this before or used VB.

I think step 1 should be to focus on the font library extension as that is key to getting the PowerPoint approach working. I will clone your copy of the TFT_ext library and create a list of comments for consideration. OK?

Sure :)

Note, if you use

tx1 = Round((Shp.Left + Shp.Table.Rows(i).Cells(j).Shape.TextFrame.TextRange.BoundLeft) * SF)                  
ty1 = Round((Shp.Top + Shp.Table.Rows(i).Cells(j).Shape.TextFrame.TextRange.BoundTop + 3) * SF) ' Todo: where comes the 3 from?

you'll get centered texts in tables for free :) Perhahps right-aligned and for other texts, too - but I have not tested this.

[Bodmer]

Thanks for the tip!

[FrankBoesing]

I've compiled ttf2bdf for windows:
https://github.com/FrankBoesing/TFT_eSPI_ext/tree/main/extras/ttf2bdf_windows

[Bodmer]

That's useful, thanks.

[Bodmer]

I have updated the VBA macro and put the updated pptm here:
https://github.com/Bodmer/Powerpoint-ILI9341_t3

I have created a pull request to Kris's repository.

[FrankBoesing]

I'll take a look :)

[Bodmer]

I have added a ReadMe to the repository here:

https://github.com/Bodmer/PowerPoint_to_sketch