Screenshare: grim preview from picker, ~70ms instead of ~1s

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

settings/hyprland.nix

@@ -117,28 +117,90 @@ in
       # or HDT. Gaming's patched Vesktop writes the time to xdph-pick-manually
       # right before asking the portal ("Pick Another Window", shift-click)
       # to get the normal picker instead.
+      #
+      # After answering, it grim-shots the selection to xdph-preview.jpg for
+      # Vesktop's dialog (~70ms vs Electron's ~1s PipeWire thumbnail). grim
+      # reads the screen, so a window that isn't visible is skipped and Vesktop
+      # falls back to the thumbnail.
       xdg.configFile."hypr/xdph.conf".text = ''
         screencopy {
           allow_token_by_default = true
-          custom_picker_binary = ${pkgs.writeShellScript "share-picker-game-first" ''
-            flag="''${XDG_RUNTIME_DIR:-/tmp}/xdph-pick-manually"
-            printf -v now '%(%s)T' -1
-            { forced=$(< "$flag"); } 2>/dev/null   # no trailing newline, so not `read`
-            echo 0 > "$flag"
+          custom_picker_binary = ${lib.getExe (pkgs.writeShellApplication {
+            name = "share-picker-game-first";
+            runtimeInputs = with pkgs; [ coreutils gawk jq grim hyprland xdg-desktop-portal-hyprland ];
+            excludeShellChecks = [ "SC2016" ];   # $ in awk/jq programs is meant literally
+            text = ''
+              run=''${XDG_RUNTIME_DIR:-/tmp}
+              flag=$run/xdph-pick-manually
+              preview=$run/xdph-preview.jpg
+              list=''${XDPH_WINDOW_SHARING_LIST-}
+              rm -f "$preview"
 
-            game=$(printf '%s' "''${XDPH_WINDOW_SHARING_LIST-}" | ${pkgs.gawk}/bin/awk '
-              BEGIN { RS = "\\[HA>\\]"; FS = "\\[H[CTE]>\\]" }
-              $2 ~ /^steam_app_/ && $3 == "Hearthstone" { hs = $1 }
-              $2 ~ /^steam_app_/ && $3 != "" && !other \
-                && $3 !~ /^(Battle\.net|Hearthstone Deck Tracker|HearthstoneOverlay)/ { other = $1 }
-              END { print hs != "" ? hs : other }')
+              printf -v now '%(%s)T' -1
+              { forced=$(< "$flag"); } 2>/dev/null || forced=0   # no trailing newline, so not `read`
+              echo 0 > "$flag"
 
-            if [ -n "$game" ] && (( now - ''${forced:-0} > 10 )); then
-              echo "[SELECTION]r/window:$game"
-              exit 0
-            fi
-            exec ${pkgs.xdg-desktop-portal-hyprland}/bin/hyprland-share-picker "$@"
-          ''}
+              # run awk program $2 over the window list as id/class/title/address
+              # columns, with want=$1
+              entries() {
+                printf '%s' "$list" | awk '
+                  BEGIN { RS = "\\[HA>\\]"; FS = "\\[H[CTE]>\\]" }
+                  { print $1 "\t" $2 "\t" $3 "\t" $4 }' | awk -F '\t' -v want="$1" "$2"
+              }
+              game=$(entries "" '
+                $2 ~ /^steam_app_/ && $3 == "Hearthstone" { hs = $1 }
+                $2 ~ /^steam_app_/ && $3 != "" && !other \
+                  && $3 !~ /^(Battle\.net|Hearthstone Deck Tracker|HearthstoneOverlay)/ { other = $1 }
+                END { print hs != "" ? hs : other }')
+
+              if [ -n "$game" ] && (( now - forced > 10 )); then
+                selection=r/window:$game
+              else
+                out=$(hyprland-share-picker "$@") || true
+                selection=''${out#*"[SELECTION]"}
+                if [ "$selection" = "$out" ]; then   # closed / failed: pass through
+                  printf '%s\n' "$out"
+                  exit 0
+                fi
+              fi
+              echo "[SELECTION]$selection"
+
+              shoot() {
+                local target=''${1#*/} where=()
+                case $target in
+                  window:*)
+                    local id=''${target#window:} addr geom
+                    if (( id < 0 )); then id=$(( id + 4294967296 )); fi   # the Qt picker prints it signed
+                    addr=$(entries "$id" '$1 == want { print $4 }')
+                    [ -n "$addr" ] || return 0
+                    geom=$(hyprctl -j clients | jq -r --arg a "$(printf '0x%x' "$addr")" \
+                      --argjson mons "$(hyprctl -j monitors)" '
+                      [$mons[] | .activeWorkspace.id, .specialWorkspace.id] as $shown
+                      | .[] | select(.address == $a and (.hidden | not))
+                      | select(.workspace.id as $w | any($shown[]; . == $w))
+                      | "\(.at[0]),\(.at[1]) \(.size[0])x\(.size[1])"')
+                    [ -n "$geom" ] || return 0
+                    where=(-g "$geom")
+                    ;;
+                  screen:*)
+                    where=(-o "''${target#screen:}")
+                    ;;
+                  region:*)
+                    local spec=''${target#region:} x y w h geom
+                    IFS=, read -r x y w h <<< "''${spec#*@}"
+                    geom=$(hyprctl -j monitors | jq -r --arg o "''${spec%@*}" \
+                      --argjson x "$x" --argjson y "$y" --arg wh "''${w}x$h" '
+                      .[] | select(.name == $o) | "\(.x + $x),\(.y + $y) \($wh)"')
+                    [ -n "$geom" ] || return 0
+                    where=(-g "$geom")
+                    ;;
+                  *) return 0 ;;
+                esac
+                grim "''${where[@]}" -s 0.5 -t jpeg -q 85 "$preview.tmp" && mv -f "$preview.tmp" "$preview"
+              }
+              shoot "$selection" > /dev/null 2>&1 < /dev/null &
+            '';
+          })}
         }
       '';