osc: use custom symbols for window controls

I was recently informed that unicode has official symbols for
window controls, and I put together a change to use them, which
worked, as long as a suitable font was installed. However, it's
not that hard to get a normal system that lacks an appropriate
font, and libass wants to print warnings if the symbols aren't
in the default font, which will almost always be true.

So, I gave up and added the symbols to the custom osd font that
we already have. This ensures they are always available, and
that they are aligned consistently on all platforms.

I took the symbols from the `symbola` font, as this has a suitable
licence and the symbols look nice enough.

Symbola Licence:

    Fonts are free for any use; they may be opened, edited,
    modified, regenerated, packaged and redistributed.

Finally, as we now have access to an un-maximize symbol, I added
logic to use it when the window is maximized.

TOOLS/mpv-osd-symbols.sfdir/font.props

@@ -22,7 +22,7 @@ OS2Version: 3
 OS2_WeightWidthSlopeOnly: 0
 OS2_UseTypoMetrics: 0
 CreationTime: 1408646554
-ModificationTime: 1492879730
+ModificationTime: 1576096543
 PfmFamily: 81
 TTFWeight: 400
 TTFWidth: 5

TOOLS/mpv-osd-symbols.sfdir/uniE112.glyph

@@ -0,0 +1,15 @@
+StartChar: uniE112
+Encoding: 57618 57618 30
+Width: 768
+VWidth: 1176
+Flags: HW
+LayerCount: 2
+Fore
+SplineSet
+512 40 m 1
+ 0 40 l 1
+ 0 168 l 1
+ 512 168 l 1
+ 512 40 l 1
+EndSplineSet
+EndChar

TOOLS/mpv-osd-symbols.sfdir/uniE113.glyph

@@ -0,0 +1,20 @@
+StartChar: uniE113
+Encoding: 57619 57619 31
+Width: 622
+VWidth: 1178
+Flags: HW
+LayerCount: 2
+Fore
+SplineSet
+768 42 m 5
+ 0 42 l 5
+ 0 746 l 5
+ 768 746 l 5
+ 768 42 l 5
+704 106 m 5
+ 704 618 l 5
+ 64 618 l 5
+ 64 106 l 5
+ 704 106 l 5
+EndSplineSet
+EndChar

TOOLS/mpv-osd-symbols.sfdir/uniE114.glyph

@@ -0,0 +1,31 @@
+StartChar: uniE114
+Encoding: 57620 57620 32
+Width: 896
+VWidth: 1178
+Flags: HW
+LayerCount: 2
+Fore
+SplineSet
+768 298 m 1
+ 576 298 l 1
+ 576 42 l 1
+ 0 42 l 1
+ 0 490 l 1
+ 192 490 l 1
+ 192 746 l 1
+ 768 746 l 1
+ 768 298 l 1
+704 362 m 1
+ 704 618 l 1
+ 256 618 l 1
+ 256 490 l 1
+ 576 490 l 1
+ 576 362 l 1
+ 704 362 l 1
+512 106 m 1
+ 512 362 l 1
+ 64 362 l 1
+ 64 106 l 1
+ 512 106 l 1
+EndSplineSet
+EndChar

TOOLS/mpv-osd-symbols.sfdir/uniE115.glyph

@@ -0,0 +1,27 @@
+StartChar: uniE115
+Encoding: 57621 57621 33
+Width: 844
+VWidth: 1112
+Flags: HW
+LayerCount: 2
+Fore
+SplineSet
+671 40 m 1
+ 575 40 l 1
+ 335 277 l 1
+ 98 40 l 1
+ -1 40 l 1
+ -1 136 l 1
+ 236 376 l 1
+ -1 613 l 1
+ -1 712 l 1
+ 98 712 l 1
+ 335 475 l 1
+ 575 712 l 1
+ 671 712 l 1
+ 671 613 l 1
+ 434 376 l 1
+ 671 139 l 1
+ 671 40 l 1
+EndSplineSet
+EndChar

player/lua/osc.lua

@@ -103,7 +103,8 @@ local osc_styles = {
     timePosBar = "{\\blur0\\bord".. user_opts.tooltipborder .."\\1c&HFFFFFF\\3c&H000000\\fs30}",
     vidtitleBar = "{\\blur0\\bord0\\1c&HFFFFFF\\3c&HFFFFFF\\fs18\\q2}",
 
-    wcButtons = "{\\1c&HFFFFFF\\fs24}",
+    wcButtons = "{\\1c&HFFFFFF\\fs24\\fnmpv-osd-symbols}",
+    wcTitle = "{\\1c&HFFFFFF\\fs24}",
     wcBar = "{\\1c&H000000}",
 }
 
@@ -134,6 +135,7 @@ local state = {
     dmx_cache = 0,
     using_video_margins = false,
     border = true,
+    maximized = false,
 }
 
 local window_control_box_width = 80
@@ -1040,33 +1042,41 @@ function window_controls(topbar)
     local third_geo =
         {x = controlbox_left + 55, y = button_y, an = 4, w = 25, h = 25}
 
-    -- Close
+    -- Window control buttons use symbols in the custom mpv osd font
+    -- because the official unicode codepoints are sufficiently
+    -- exotic that a system might lack an installed font with them,
+    -- and libass will complain that they are not present in the
+    -- default font, even if another font with them is available.
+
+    -- Close: 🗙
     ne = new_element("close", "button")
-    ne.content = "\226\152\146"
+    ne.content = "\238\132\149"
     ne.eventresponder["mbtn_left_up"] =
         function () mp.commandv("quit") end
     lo = add_layout("close")
     lo.geometry = alignment == "left" and first_geo or third_geo
     lo.style = osc_styles.wcButtons
 
-    -- Minimize
+    -- Minimize: 🗕
     ne = new_element("minimize", "button")
-    ne.content = "\226\154\128"
+    ne.content = "\238\132\146"
     ne.eventresponder["mbtn_left_up"] =
         function () mp.commandv("cycle", "window-minimized") end
     lo = add_layout("minimize")
     lo.geometry = alignment == "left" and second_geo or first_geo
     lo.style = osc_styles.wcButtons
 
-    -- Maximize
+    -- Maximize: 🗖 /🗗
     ne = new_element("maximize", "button")
-    ne.content = "\226\150\163"
+    if state.maximized then
+        ne.content = "\238\132\148"
+    else
+        ne.content = "\238\132\147"
+    end
     ne.eventresponder["mbtn_left_up"] =
         function () mp.commandv("cycle", "window-maximized") end
     lo = add_layout("maximize")
     lo.geometry = alignment == "left" and third_geo or second_geo
-    -- At least with default Ubuntu fonts, this symbol is differently aligned
-    lo.geometry.y = lo.geometry.y - 2
     lo.style = osc_styles.wcButtons
 
     -- deadzone below window controls
@@ -1097,7 +1107,7 @@ function window_controls(topbar)
     lo.geometry =
         { x = titlebox_left, y = wc_geo.y - 3, an = 1, w = titlebox_w, h = wc_geo.h }
     lo.style = string.format("%s{\\clip(%f,%f,%f,%f)}",
-        osc_styles.wcButtons,
+        osc_styles.wcTitle,
         titlebox_left, wc_geo.y - wc_geo.h, titlebox_w, wc_geo.y + wc_geo.h)
 end
 
@@ -2500,6 +2510,12 @@ mp.observe_property("border", "bool",
         request_init()
     end
 )
+mp.observe_property("window-maximized", "bool",
+    function(name, val)
+        state.maximized = val
+        request_init()
+    end
+)
 mp.observe_property("idle-active", "bool",
     function(name, val)
         state.idle = val