Fix wallpaper and bar rendering when scale >1

We track the scale for wallpaper and render now and have to re-render
when the  scale changes. For the bar, this includes recreated the
fcft fonts.

docs/TODO.md

@@ -3,7 +3,7 @@
 These are in rough order of my priority, though no promises I do them in this order.
 
 - [ ] Implement a river-tag-overlay clone
-- [ ] Implement an optional clock bar
+- [ ] Add options to the bar and river-tag-overlay
 - [ ] Make a Rect struct to combine x, y, width, and height
 - [ ] Support window rules (float/tags/SSD by app-id/title)
 - [ ] Support overriding config location
@@ -28,3 +28,4 @@ These are in rough order of my priority, though no promises I do them in this or
 - [x] Support per-host config using properties
 - [x] Implement primary count/ratio per tagmask
 - [x] Add primary_count and primary_ratio to Config
+- [x] Implement an optional clock bar

src/Bar.zig

@@ -4,14 +4,17 @@
 
 const Bar = @This();
 
+/// Standard base DPI at a scale of 1
+const base_dpi = 96;
+
 context: *Context,
 
-// TODO: Get this in Config then save in Context
-fonts: *fcft.Font,
 /// The timezone of the computer.
 timezone: zeit.timezone.TimeZone,
 
-/// The output that this Bar is on
+fonts: *fcft.Font,
+font_scale: u31 = 0,
+
 output: *Output,
 
 // Bar geometry
@@ -34,7 +37,7 @@ pub fn init(context: *Context, output: *Output) !Bar {
 
     return .{
         .context = context,
-        .fonts = try getFcftFonts("monospace:size=14"),
+        .fonts = try getFcftFonts("monospace:size=14", 1),
         .timezone = timezone,
         .output = output,
     };
@@ -50,8 +53,8 @@ pub fn initSurface(bar: *Bar) !void {
     const context = bar.context;
 
     // TODO: Add padding to config
-    const padding = 5;
+    const vertical_padding = 5;
-    const bar_height: u31 = @intCast(bar.fonts.height + 2 * padding);
+    const bar_height: u31 = @intCast(bar.fonts.height + 2 * vertical_padding);
 
     const wl_surface = try context.wl_compositor.createSurface();
     errdefer wl_surface.destroy();
@@ -99,7 +102,11 @@ pub fn layerSurfaceListener(
             const width: u31 = @intCast(ev.width);
             const height: u31 = @intCast(ev.height);
 
-            if (bar.configured and bar.width == width and bar.height == height) {
+            if (bar.configured and
+                bar.width == width and
+                bar.height == height and
+                bar.output.scale == bar.font_scale)
+            {
                 if (bar.wl_surface) |wl_surface| {
                     wl_surface.commit();
                 } else {
@@ -143,6 +150,13 @@ pub fn render(bar: *Bar) !void {
 
     const scale = bar.output.scale;
 
+    // Recreate fonts at the output's new scale
+    if (scale != bar.font_scale) {
+        bar.fonts.destroy();
+        bar.fonts = try getFcftFonts("monospace:size=14", scale);
+        bar.font_scale = scale;
+    }
+
     // Scaled width/height
     const render_width = bar.width * scale;
     const render_height = bar.height * scale;
@@ -210,8 +224,9 @@ pub fn render(bar: *Bar) !void {
 
     // Finally, attach the buffer to the surface
     const wl_surface = bar.wl_surface orelse return;
+    wl_surface.setBufferScale(scale);
     wl_surface.attach(buffer.wl_buffer, 0, 0);
-    wl_surface.damageBuffer(0, 0, bar.width, bar.height);
+    wl_surface.damageBuffer(0, 0, render_width, render_height);
     wl_surface.commit();
 }
 
@@ -318,8 +333,8 @@ fn renderGlyphs(
     }
 }
 
-// Borrowed from https://git.sr.ht/~novakane/zig-fcft-example
+// Borrowed and modified from https://git.sr.ht/~novakane/zig-fcft-example
-fn getFcftFonts(fonts: []const u8) !*fcft.Font {
+fn getFcftFonts(fonts: []const u8, scale: u31) !*fcft.Font {
     // Create an arena to free just for this function;
     // It makes cleaning up the ArrayList easier.
     var arena = std.heap.ArenaAllocator.init(utils.gpa);
@@ -330,8 +345,17 @@ fn getFcftFonts(fonts: []const u8) !*fcft.Font {
 
     var it = mem.tokenizeScalar(u8, fonts, ',');
     while (it.next()) |font| {
+        if (scale > 1) {
+            // If scale >1, we append :dpi so we can scale the font
+            const scaled = try arena_alloc.dupeZ(
+                u8,
+                try std.fmt.allocPrint(arena_alloc, "{s}:dpi={}", .{ font, @as(u32, base_dpi) * scale }),
+            );
+            try list.append(arena_alloc, scaled);
+        } else {
             try list.append(arena_alloc, try arena_alloc.dupeZ(u8, font));
         }
+    }
 
     const fcft_fonts = try fcft.Font.fromName(list.items[0..], null);
     errdefer fcft_fonts.destroy();

src/Config.zig

@@ -477,7 +477,22 @@ fn loadKeybindsChildBlock(config: *Config, parser: *kdl.Parser, hostname: ?[]con
                                 logWarnMissingNodeArg(name, "command");
                                 continue;
                             });
-                            const split_exec = try utils.tokenizeToOwnedSlices(exec_str, ' ');
+                            var split_exec = try utils.tokenizeToOwnedSlices(exec_str, ' ');
+                            if (split_exec.len > 0) {
+                                // Expand ~ in executable paths
+                                const expanded = expandTilde(split_exec[0]) catch |e| {
+                                    if (e == error.HomeNotSet) {
+                                        // No ~, just return what we had.
+                                        break :sw .{ .spawn = split_exec };
+                                    } else {
+                                        return e;
+                                    }
+                                };
+                                // tokenizeToOwnedSlices dupes each token, so we have to
+                                // free the original value before replacing it.
+                                utils.gpa.free(split_exec[0]);
+                                split_exec[0] = expanded;
+                            }
                             break :sw .{ .spawn = split_exec };
                         },
                         .change_ratio => {

src/Output.zig

@@ -29,6 +29,7 @@ usable_width: u31 = 0,
 usable_height: u31 = 0,
 
 // Information for this Output's wallpaper
+wallpaper_render_scale: u31 = 0,
 wallpaper_render_width: u31 = 0,
 wallpaper_render_height: u31 = 0,
 wl_surface: ?*wl.Surface = null,
@@ -265,6 +266,18 @@ fn wlOutputListener(_: *wl.Output, event: wl.Output.Event, output: *Output) void
                     log.err("failed to init bar for {s}: {}", .{ output_name, err });
                     return;
                 };
+                // Re-render bar if the scale changed
+                if (bar.configured and output.scale != bar.font_scale) {
+                    bar.render() catch |err| {
+                        log.err("Bar render failed: {}", .{err});
+                    };
+                }
+            }
+            // Re-render wallpaper if scale changed
+            if (output.configured and output.scale != output.wallpaper_render_scale) {
+                output.renderWallpaper() catch |err| {
+                    log.err("Wallpaper render failed: {}", .{err});
+                };
             }
         },
         .scale => |ev| {
@@ -361,7 +374,11 @@ fn wallpaperLayerSurfaceListener(layer_surface: *zwlr.LayerSurfaceV1, event: zwl
             const width: u31 = @intCast(ev.width);
             const height: u31 = @intCast(ev.height);
 
-            if (output.configured and output.wallpaper_render_width == width and output.wallpaper_render_height == height) {
+            if (output.configured and
+                output.wallpaper_render_width == width and
+                output.wallpaper_render_height == height and
+                output.scale == output.wallpaper_render_scale)
+            {
                 if (output.wl_surface) |wl_surface| {
                     wl_surface.commit();
                 } else {
@@ -393,7 +410,7 @@ fn calculateScale(image_dimension: c_int, output_dimension: u31, scale: u31) f64
     return numerator / denominator;
 }
 
-/// Calculates (image_dimension / dimension_scale - output_dimension) / 2 / dimension_scale;
+/// Calculates (image_dimension / dimension_scale - output_dimension) / 2 / dimension_scale
 fn calculateTransform(image_dimension: c_int, output_dimension: u31, dimension_scale: f64) f64 {
     const numerator1: f64 = @floatFromInt(image_dimension);
     const denominator1: f64 = dimension_scale;
@@ -441,8 +458,8 @@ pub fn renderWallpaper(output: *Output) !void {
 
     // Calculate translation offsets to center the image on the output.
     // If the scaled image is larger than the output, the offset crops equally from both sides.
-    const tx: f64 = calculateTransform(image_width, width, sx);
+    const tx: f64 = calculateTransform(image_width, width * scale, sx);
-    const ty: f64 = calculateTransform(image_height, height, sy);
+    const ty: f64 = calculateTransform(image_height, height * scale, sy);
 
     // Build a combined source-to-destination transform matrix.
     // Pixman transforms map destination pixels back to source pixels, so:
@@ -473,6 +490,8 @@ pub fn renderWallpaper(output: *Output) !void {
     wl_surface.attach(buffer.wl_buffer, 0, 0);
     wl_surface.damageBuffer(0, 0, width * scale, height * scale);
     wl_surface.commit();
+
+    output.wallpaper_render_scale = scale;
 }
 
 pub fn manage(output: *Output) void {

src/utils.zig

@@ -103,7 +103,7 @@ pub fn parseModifiers(s: []const u8) !?river.SeatV1.Modifiers {
     return modifiers;
 }
 
-pub fn tokenizeToOwnedSlices(input: []const u8, delimiter: u8) ![]const []const u8 {
+pub fn tokenizeToOwnedSlices(input: []const u8, delimiter: u8) ![][]const u8 {
     var list: std.ArrayList([]const u8) = .empty;
     var it = std.mem.tokenizeScalar(u8, input, delimiter);
     while (it.next()) |part| {