The Window size (client area) is incorrect when using Windows display driver.

[sliang951753]

LVGL version

v9.0.0

What happened?

When using lv_windows_create_display() to create LVGL display, the Window's client area always smaller than the specified screen resolution.
for example, lv_windows_create_display(L"LVGL Window", 1024, 600, 100, true, false);
then, the created window is at the resolution of 1024*600, however, its client area is smaller and about to 1000 * 550.

This is because the specified display resolution does not consider the window caption and client edge size.

Here's a possible fix for this issue.
In lv_windows_display_thread_entrypoint() function, calling AdjustWindowRectEx before CreateWindowExW.

` RECT rc = {0, 0, data->hor_res, data->ver_res};
AdjustWindowRectEx(&rc, window_style, FALSE, WS_EX_CLIENTEDGE);

HWND window_handle = CreateWindowExW(
                         WS_EX_CLIENTEDGE,
                         L"LVGL.Window",
                         data->title,
                         window_style,
                         CW_USEDEFAULT,
                         0,
                         rc.right - rc.left,
                         rc.bottom - rc.top,
                         NULL,
                         NULL,
                         NULL,
                         data);`

How to reproduce?

No response

[lvgl-bot]

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[kisvegabor]

Thank you for reporting it!

@MouriNaruto could you take look at this issue?

[vwheeler63]

> HWND window_handle = CreateWindowExW(
>                          WS_EX_CLIENTEDGE,
>                          L"LVGL.Window",
>                          data->title,
>                          window_style,
>                          CW_USEDEFAULT,
>                          0,
>                          rc.right - rc.left,
>                          rc.bottom - rc.top,
>                          NULL,
>                          NULL,
>                          NULL,
>                          data);

I believe there are also 2 one-off errors in this call. Specifically:

width should be = rc.right - rc.left + 1 + (2 * edge_width);
height should be = rc.bottom - rc.top + 1 + (2 * edge_width) + title_bar_height;

or

width should be = rc.right - rc.left + 1 + (edge_width << 1);
height should be = rc.bottom - rc.top + 1 + (edge_width << 1) + title_bar_height;

if your compiler doesn't optimize multiplying by 2.

I am a little rusty on CreateWindowExW(), but what I remember about Win32 is that (using Win32 data):

Width = Right - Left
Height = Bottom - Top

and I am 100% certain that:

Right = 1 pixel PAST right edge, and
Bottom = 1 pixel PAST bottom edge.

Note: There are ways to create a window where the width and height passed are for the CLIENT AREA, which is what is wanted. This question/answer on stackexchange.com covers one way to do that.

Kind regards,
Vic

[MouriNaruto]

I will try to fix that.

Kenji Mouri

[lvgl-bot]

We need some feedback on this issue.

Now we mark this as "stale" because there was no activity here for 14 days.

Remove the "stale" label or comment else this will be closed in 7 days.

[kisvegabor]

@MouriNaruto did you have time to look into this?

[MouriNaruto]

I will look into this issue in the recent days.

Kenji Mouri

[lvgl-bot]

We need some feedback on this issue.

Now we mark this as "Abandoned" because there was no activity here for 14 days.

Remove the "Stale" label or comment else this will be closed in 7 days.

[MouriNaruto]

not stale