Add transparency for unfocused panes

Author: max-legrand

src/Surface.zig

@@ -590,10 +590,8 @@ const fallback_palette: [16]vaxis.Cell.Color = .{
     .{ .rgb = .{ 0xff, 0xff, 0xff } }, // Bright White
 };
 
-const DIM_UNFOCUSED: f32 = 0.05;
-
-pub fn render(self: *const Surface, win: vaxis.Window, focused: bool) void {
-    const dim_factor: f32 = if (focused) 0.0 else DIM_UNFOCUSED;
+pub fn render(self: *const Surface, win: vaxis.Window, focused: bool, colors: ?*const TerminalColors, dim_factor: f32) void {
+    _ = colors; // Colors are stored in self.colors
 
     for (0..self.rows) |row| {
         for (0..self.cols) |col| {
@@ -620,6 +618,9 @@ pub fn render(self: *const Surface, win: vaxis.Window, focused: bool) void {
 }
 
 fn applyDimming(self: *const Surface, cell: *vaxis.Cell, dim_factor: f32) bool {
+    // Skip dimming for default backgrounds to preserve transparency
+    if (cell.style.bg == .default) return false;
+
     const bg_rgb = self.resolveBgColor(cell.style.bg) orelse return false;
     const dimmed_bg = TerminalColors.reduceContrast(bg_rgb, dim_factor);
     cell.style.bg = .{ .rgb = dimmed_bg };
@@ -630,7 +631,7 @@ fn resolveBgColor(self: *const Surface, bg: vaxis.Cell.Color) ?[3]u8 {
     return switch (bg) {
         .rgb => |rgb| rgb,
         .index => |idx| self.resolvePaletteColor(idx),
-        .default => self.resolveDefaultBg(),
+        .default => null, // Don't resolve default - preserve transparency
     };
 }
 

src/client.zig

@@ -1537,8 +1537,148 @@ pub const App = struct {
         }
     }
 
+    fn applyDimToStyle(self: *App, style: vaxis.Style, dim_factor: f32) vaxis.Style {
+        if (dim_factor == 0.0) return style;
+
+        var dimmed = style;
+
+        // Apply dimming to foreground color
+        if (dimmed.fg != .default) {
+            const fg_rgb = self.resolveColor(dimmed.fg);
+            if (fg_rgb) |rgb| {
+                dimmed.fg = .{ .rgb = Surface.TerminalColors.reduceContrast(rgb, dim_factor * 0.5) };
+            }
+        }
+
+        // Apply dimming to background color
+        if (dimmed.bg != .default) {
+            const bg_rgb = self.resolveColor(dimmed.bg);
+            if (bg_rgb) |rgb| {
+                dimmed.bg = .{ .rgb = Surface.TerminalColors.reduceContrast(rgb, dim_factor) };
+            }
+        }
+
+        return dimmed;
+    }
+
+    fn resolveColor(self: *App, color: vaxis.Cell.Color) ?[3]u8 {
+        return switch (color) {
+            .rgb => |rgb| rgb,
+            .index => |idx| blk: {
+                if (idx >= 16) break :blk null;
+                if (self.colors.palette[idx]) |c_val| {
+                    break :blk switch (c_val) {
+                        .rgb => |rgb| rgb,
+                        else => null,
+                    };
+                }
+                break :blk null;
+            },
+            .default => blk: {
+                if (self.colors.bg) |bg| {
+                    break :blk switch (bg) {
+                        .rgb => |rgb| rgb,
+                        else => null,
+                    };
+                }
+                break :blk null;
+            },
+        };
+    }
+
     fn renderWidget(self: *App, w: widget.Widget, win: vaxis.Window) !void {
-        try w.renderTo(win, self.allocator);
+        switch (w.kind) {
+            .surface => |surf| {
+                if (self.surfaces.get(surf.pty_id)) |surface| {
+                    // Check for resize mismatch and send resize request if needed
+                    if (surface.rows != w.height or surface.cols != w.width) {
+                        log.debug("renderWidget: surface resize needed for pty {}: {}x{} -> {}x{}", .{
+                            surf.pty_id,
+                            surface.cols,
+                            surface.rows,
+                            w.width,
+                            w.height,
+                        });
+                        self.sendResize(surf.pty_id, w.height, w.width) catch |err| {
+                            log.err("Failed to send resize: {}", .{err});
+                        };
+                    }
+                    // Calculate dim factor based on focus
+                    const dim_factor: f32 = if (w.focus) 0.0 else self.ui.dim_factor;
+                    surface.render(win, w.focus, &self.colors, dim_factor);
+                }
+            },
+            .text => {
+                // Use renderTo for text widgets
+                try w.renderTo(win, self.allocator);
+            },
+            .box => |b| {
+                const chars = b.borderChars();
+                // Apply dimming to border style if not focused
+                const dim_factor: f32 = if (w.focus) 0.0 else self.ui.dim_factor;
+                const style = self.applyDimToStyle(b.style, dim_factor);
+
+                log.debug("render box: w={} h={} focus={} dim_factor={d}", .{ win.width, win.height, w.focus, dim_factor });
+
+                // Fill background for the entire box area
+                if (style.bg != .default) {
+                    for (0..win.height) |row| {
+                        for (0..win.width) |col| {
+                            win.writeCell(@intCast(col), @intCast(row), .{
+                                .char = .{ .grapheme = " ", .width = 1 },
+                                .style = style,
+                            });
+                        }
+                    }
+                }
+
+                // Render border if not none
+                if (b.border != .none and win.width >= 2 and win.height >= 2) {
+                    win.writeCell(0, 0, .{ .char = .{ .grapheme = chars.tl, .width = 1 }, .style = style });
+                    win.writeCell(win.width - 1, 0, .{ .char = .{ .grapheme = chars.tr, .width = 1 }, .style = style });
+                    win.writeCell(0, win.height - 1, .{ .char = .{ .grapheme = chars.bl, .width = 1 }, .style = style });
+                    win.writeCell(win.width - 1, win.height - 1, .{ .char = .{ .grapheme = chars.br, .width = 1 }, .style = style });
+
+                    for (1..win.width - 1) |col| {
+                        win.writeCell(@intCast(col), 0, .{ .char = .{ .grapheme = chars.h, .width = 1 }, .style = style });
+                        win.writeCell(@intCast(col), win.height - 1, .{ .char = .{ .grapheme = chars.h, .width = 1 }, .style = style });
+                    }
+
+                    for (1..win.height - 1) |row| {
+                        win.writeCell(0, @intCast(row), .{ .char = .{ .grapheme = chars.v, .width = 1 }, .style = style });
+                        win.writeCell(win.width - 1, @intCast(row), .{ .char = .{ .grapheme = chars.v, .width = 1 }, .style = style });
+                    }
+                }
+
+                // Render child widget if present
+                const inner_win = win.child(.{
+                    .x_off = if (b.border != .none) 1 else 0,
+                    .y_off = if (b.border != .none) 1 else 0,
+                    .width = if (b.border != .none and win.width >= 2) win.width - 2 else win.width,
+                    .height = if (b.border != .none and win.height >= 2) win.height - 2 else win.height,
+                });
+                try self.renderWidget(b.child.*, inner_win);
+            },
+            .positioned => |pos| {
+                const child_win = win.child(.{
+                    .x_off = pos.x orelse 0,
+                    .y_off = pos.y orelse 0,
+                    .width = pos.child.width,
+                    .height = pos.child.height,
+                });
+                try self.renderWidget(pos.child.*, child_win);
+            },
+            .text_input,
+            .list,
+            .padding,
+            .column,
+            .row,
+            .stack,
+            => {
+                // These widgets use renderTo for now
+                try w.renderTo(win, self.allocator);
+            },
+        }
     }
 
     pub fn scheduleRender(self: *App) !void {

src/ui.zig

@@ -87,6 +87,7 @@ pub const UI = struct {
     get_session_name_ctx: *anyopaque = undefined,
     rename_session_callback: ?*const fn (ctx: *anyopaque, new_name: []const u8) anyerror!void = null,
     rename_session_ctx: *anyopaque = undefined,
+    dim_factor: f32 = 0.025,
     text_inputs: std.AutoHashMap(u32, *TextInput),
     next_text_input_id: u32 = 1,
 
@@ -215,6 +216,19 @@ pub const UI = struct {
         // Store pointer to self in registry for static functions to use
         self.lua.pushLightUserdata(self);
         self.lua.setField(ziglua.registry_index, "prise_ui_ptr");
+
+        // Apply any pending dim_factor that was set during init.lua
+        _ = self.lua.getField(ziglua.registry_index, "_pending_dim_factor");
+        if (self.lua.typeOf(-1) == .number) {
+            const pending_dim = self.lua.toNumber(-1) catch 0.025;
+            log.debug("setLoop: applying pending dim_factor={d}", .{pending_dim});
+            self.dim_factor = @floatCast(pending_dim);
+            self.lua.pop(1);
+            self.lua.pushNil();
+            self.lua.setField(ziglua.registry_index, "_pending_dim_factor");
+        } else {
+            self.lua.pop(1);
+        }
     }
 
     pub fn setExitCallback(self: *UI, ctx: *anyopaque, cb: *const fn (ctx: *anyopaque) void) void {
@@ -375,6 +389,14 @@ pub const UI = struct {
         lua.pushFunction(ziglua.wrap(renameSession));
         lua.setField(-2, "rename_session");
 
+        // Register set_dim_factor
+        lua.pushFunction(ziglua.wrap(setDimFactor));
+        lua.setField(-2, "set_dim_factor");
+
+        // Register get_dim_factor
+        lua.pushFunction(ziglua.wrap(getDimFactor));
+        lua.setField(-2, "get_dim_factor");
+
         // Register create_text_input
         lua.pushFunction(ziglua.wrap(createTextInput));
         lua.setField(-2, "create_text_input");
@@ -639,6 +661,43 @@ pub const UI = struct {
         return 1;
     }
 
+    fn getDimFactor(lua: *ziglua.Lua) i32 {
+        _ = lua.getField(ziglua.registry_index, "prise_ui_ptr");
+        const ui_ptr = lua.toPointer(-1) catch {
+            lua.pushNumber(0.025);
+            return 1;
+        };
+        lua.pop(1);
+
+        const ui: *UI = @ptrCast(@alignCast(@constCast(ui_ptr)));
+        lua.pushNumber(ui.dim_factor);
+        return 1;
+    }
+
+    fn setDimFactor(lua: *ziglua.Lua) i32 {
+        const dim: f64 = lua.toNumber(1) catch 0.025;
+
+        // Try to get the UI pointer and set it directly
+        _ = lua.getField(ziglua.registry_index, "prise_ui_ptr");
+        const ui_ptr_result = lua.toPointer(-1);
+        lua.pop(1);
+
+        if (ui_ptr_result) |ui_ptr| {
+            const ui: *UI = @ptrCast(@alignCast(@constCast(ui_ptr)));
+            log.debug("setDimFactor: setting dim_factor to {d}", .{dim});
+            ui.dim_factor = @floatCast(dim);
+            lua.pushBoolean(true);
+            return 1;
+        } else |_| {
+            // UI pointer not available yet (we're in init.lua), store the value for later
+            log.debug("setDimFactor: storing pending dim_factor={d}", .{dim});
+            lua.pushNumber(dim);
+            lua.setField(ziglua.registry_index, "_pending_dim_factor");
+            lua.pushBoolean(true);
+            return 1;
+        }
+    }
+
     fn detach(lua: *ziglua.Lua) i32 {
         _ = lua.getField(ziglua.registry_index, "prise_ui_ptr");
         const ui = lua.toUserdata(UI, -1) catch {

src/widget.zig

@@ -252,7 +252,7 @@ pub const Widget = struct {
     pub fn renderTo(self: *const Widget, win: vaxis.Window, allocator: std.mem.Allocator) !void {
         switch (self.kind) {
             .surface => |surf| {
-                surf.surface.render(win, self.focus);
+                surf.surface.render(win, self.focus, null, 0.0);
             },
             .text_input => |ti| {
                 ti.input.updateScrollOffset(@intCast(win.width));