Release of touch input device results in wrong coordinates while using "invert-x/y" (lvgl-pointer-input) due to double inversion of coordinates

[Benni77]

I'm wondering if this is a bug with request for confirmation before I open an issue:

I'm using a gc9a01 display with CST816S touch controller with lvgl.
When I use the lvgl Dropdown Widget the selection of the list options is not working correctly.
Digging into it made me realize this only happens if invert-x or invert-y (propably with swap-xy as well) configuration is activated in zephyr,lvgl-pointer-input device:

lvgl_pointer {
     compatible = "zephyr,lvgl-pointer-input";
     input = <&cst816s>;
     invert-x;
     invert-y;
};

So i digged deeper:
In the input drivers input_cst816s.c processing function (cst816s_process()) a input is reported on release of the touch device in the else statement:

	if (pressed) {
		input_report_abs(dev, INPUT_ABS_X, col, false, K_FOREVER);
		input_report_abs(dev, INPUT_ABS_Y, row, false, K_FOREVER);
		input_report_key(dev, INPUT_BTN_TOUCH, 1, true, K_FOREVER);
	} else {
	        input_report_key(dev, INPUT_BTN_TOUCH, 0, true, K_FOREVER);
	}

Now in the lvgl_pointer_process_event() function in the lvgl_pointer_input.c file the coordinates of the input event get inverted:

	if (cfg->invert_x) {
		if (cap->current_orientation == DISPLAY_ORIENTATION_NORMAL ||
		    cap->current_orientation == DISPLAY_ORIENTATION_ROTATED_180) {
			point->x = cap->x_resolution - point->x;
		} else {
			point->x = cap->y_resolution - point->x;
		}
	}

	if (cfg->invert_y) {
		if (cap->current_orientation == DISPLAY_ORIENTATION_NORMAL ||
		    cap->current_orientation == DISPLAY_ORIENTATION_ROTATED_180) {
			point->y = cap->y_resolution - point->y;
		} else {
			point->y = cap->x_resolution - point->y;
		}
	}

Problem: Since this inversion also happens on the "RELEASE" event without new coordinates passed by the input device this results in a double inversion of the last coordinates: First when new coordinates are passed, second when "RELEASE" is passed.

Result: Since the Dropdown widget uses the double inverted coordinates from the "RELEASE" event, this unfortunately results in a malfunction of the widget. The list items can not be selected correctly.

For me it looks like a bug in the lvgl_pointer_process_event() function, which should not invert on "RELEASE" event, what do you guys think?

Cheers
Benjamin

[faxe1008]

@Benni77 thanks for raising that discussion. There is a PR pending which should fix your reported issue:
#67508

I misread that, the PR deals with swap-xy and not the invert. I will check your suggestion then.

[faxe1008]

@Benni77 I created an issue from this discussion and submitted a PR that should fix your issue:
#70541
Can you verify the fix?

[Benni77]

Works 👍️

Thanks!