Constrain thumbnail within the window

Don't let the thumbnail go out of view near left or right edge.
Before, the thumbnail might be partially hidden if the window was
particularly small. Doesn't happen much on the built-in OSCs, topbar
and bottombar were the worst (albeit barely) offenders.

Author: TheAMM

src/options.lua

@@ -64,6 +64,9 @@ local thumbnailer_options = {
     -- Alpha: 0 - fully opaque, 255 - transparent
     background_alpha = 80,
 
+    -- Keep thumbnail on the screen near left or right side
+    constrain_to_screen = true,
+
     -- The maximum dimensions of the thumbnails (pixels)
     thumbnail_width = 200,
     thumbnail_height = 200,

src/patched_osc.lua

@@ -116,6 +116,8 @@ function display_thumbnail(pos, value, ass)
         target_position = duration * (value / 100)
 
         local msx, msy = get_virt_scale_factor()
+        local osd_w, osd_h = mp.get_osd_size()
+
         local thumb_size = Thumbnailer.state.thumbnail_size
         local thumb_path, thumb_index, closest_index = Thumbnailer:get_thumbnail_path(target_position)
 
@@ -147,6 +149,18 @@ function display_thumbnail(pos, value, ass)
         local ass_h = thumb_size.h * msy
         local y_offset = get_thumbnail_y_offset(thumb_size, 1)
 
+        -- Constrain thumbnail display to window
+        -- (ie. don't let it go off-screen left/right)
+        if thumbnailer_options.constrain_to_screen and osd_w > (ass_w + pad.l + pad.r)/msx then
+            local padded_left = (pad.l + (ass_w / 2))
+            local padded_right = (pad.r + (ass_w / 2))
+            if pos.x - padded_left < 0 then
+                pos.x = padded_left
+            elseif pos.x + padded_right > osd_w*msx then
+                pos.x = osd_w*msx - padded_right
+            end
+        end
+
         local text_h = 30 * msy
         local bg_h = ass_h + (display_progress and text_h or 0)
         local bg_left = pos.x - ass_w/2