[BUG] TFT35 does not preview only 95x95 sketches

[MrKuskov]

Description

The TFT35 preview sketches with a resolution of 95x95 G-code. When you specify the BTT TT thumbnail format and size 95x95 in OrcaSlicer, they are not displayed. The Cura plugin generates 5 thumbnail resolutions at once. I have experimentally established that the minimum number of image resolutions required to display on the TFT35 B1 V3 screen is 3 pieces: 70x70, 95x80 and 95x95. I have attached all the options in the archive. Only one of them displays a thumbnail on the screen.
gcode.zip

[rlneumiller]

Which one of the five gcode files displays the thumbnail properly for you?

[MrKuskov]

@rlneumiller Sorry. None of them. I forgot to attach it. there must be 3 resolutions in the file 70x70, 95x80 and 95x95 for the thumbnail to be displayed.
OrcaCube_PETG_1h52m.zip

[rlneumiller]

This looks like an issue with the gcode output of your slicer (assuming that THUMBNAIL_PARSER = 1 was set in Configuration.h used to build your firmware)

The thumbnail signatures in the gcode files you've provided that contain a single thumbnail are not formatted properly.
For a single thumbnail in RGB565 format with a size of 0x5Fx5F (95x95 dec), your slicer needs to write the following signature at the top of the thumbnail data in the gcode file:
; bigtree thumbnail begin 005f005f

Here is a corrected version of your 95.gcode that should work.
corrected-95.zip

If this doesn't work and you are building your own firmware, set THUMBNAIL_PARSER = 1 in your Configuration.h (yours is probably set to THUMBNAIL_PARSER = 0).

[MrKuskov]

@rlneumiller unfortunately, Your corrected file does not display a thumbnail, and my version of Configuration.h does not have a THUMBNAIL_PARSER
https://github.com/MrKuskov/Configurations/blob/patch-1/config/examples/BIQU/B1/Configuration.h

[rlneumiller]

The Marlin default setting for THUMBNAIL_PARSER is THUMBNAIL_PARSER = 0 (which requires 3 thumbnails in the gcode file)
If you add THUMBNAIL_PARSER = 1 to the end of your Configuration.h and rebuild\flash the firmware for your printer, the gcode in corrected-95.zip should then work as expected.

[MrKuskov]

@rlneumiller I made changes to Marlin #define THUMBNAIL_PARSER 1 And it doesn't work. with the file corrected-95.zip . And I don't understand how changes in Marlin can affect what is displayed on the TFT35 display, because the thumbnail is read before the file is sent to print.

[rlneumiller]

Apologies. I referenced Marlin in error and lost sight of the fact that this display is essentially a remote control for Marlin.

Your desired behavior would require adding functionality to TFT to allow for control of the thumbnail format via a setting within TFT's config.ini.

You could still workaround by modification of Configuration.h as described earlier but within the TFT source tree (see below), which would then require rebuilding BIGTREE_TFT35_V3.0_B1.27.x.bin (or whichever bin matches your hardware), and ensuring that your slicer is outputting the proper thumbnail header.

See: https://github.com/bigtreetech/BIGTREETECH-TouchScreenFirmware/blob/master/TFT/src/User/Configuration.h

Ultimately this issue is more of a feature request than a bug.

[MrKuskov]

@rlneumiller Thank you for pointing out the course of action. I have reassembled the firmware for the TFT screen. With the THUMBNAIL_PARSER =1 parameter, thumbnails are displayed with a delay, but they did not appear for the corrected-95 file. Therefore, I use the THUMBNAIL_PARSER =2 parameter, in the slicer settings I chose the PNG format and the sketch size 95x95, gcode turns out to be smaller than BTT 70x70, 95x80, 95x95. I will have to choose to display quickly or a smaller file)))

Ultimately this issue is more of a feature request than a bug.
This is a bug. That's the gist of it.

I think it would be best, if only the necessary blocks were generated depending on what is entered in the corresponding field:

resolution	TFT	necessary gode-blocks
70x70	TFT24 / TFT28	1st
95x80	TFT43 / TFT50	1st & 2nd
95x95	TFT35	1st, 2nd & 3rd
160x140	TFT70	1st, 2nd, 3rd & 4th

Originally posted by @discip in SoftFever/OrcaSlicer#1894 (comment)

This is an obvious loop nesting error. It turns out that each subsequent screen size requires the presence of a thumbnail in Gcode for the previous screen