initial padding options

src/Window.zig

@@ -260,7 +260,12 @@ pub fn create(alloc: Allocator, app: *App, config: *const Config) !*Window {
     errdefer font_group.deinit(alloc);
 
     // Create our terminal grid with the initial window size
-    var renderer_impl = try Renderer.init(alloc, font_group);
+    var renderer_impl = try Renderer.init(alloc, .{
+        .font_group = font_group,
+        .padding = .{
+            .balance = config.@"window-padding-balance",
+        },
+    });
     errdefer renderer_impl.deinit();
     renderer_impl.background = .{
         .r = config.background.r,

src/config.zig

@@ -89,6 +89,27 @@ pub const Config = struct {
     ///
     keybind: Keybinds = .{},
 
+    /// Window padding. This applies padding between the terminal cells and
+    /// the window border. The "x" option applies to the left and right
+    /// padding and the "y" option is top and bottom. The value is in points,
+    /// meaning that it will be scaled appropriately for screen DPI.
+    @"window-padding-x": u32 = 0,
+    @"window-padding-y": u32 = 0,
+
+    /// The viewport dimensions are usually not perfectly divisible by
+    /// the cell size. In this case, some extra padding on the end of a
+    /// column and the bottom of the final row may exist. If this is true,
+    /// then this extra padding is automatically balanced between all four
+    /// edges to minimize imbalance on one side. If this is false, the top
+    /// left grid cell will always hug the edge with zero padding other than
+    /// what may be specified with the other "window-padding" options.
+    ///
+    /// If other "window-padding" fields are set and this is true, this will
+    /// still apply. The other padding is applied first and may affect how
+    /// many grid cells actually exist, and this is applied last in order
+    /// to balance the padding given a certain viewport size and grid cell size.
+    @"window-padding-balance": bool = true,
+
     /// Additional configuration files to read.
     @"config-file": RepeatableString = .{},
 

src/renderer.zig

@@ -14,6 +14,7 @@ pub usingnamespace @import("renderer/message.zig");
 pub usingnamespace @import("renderer/size.zig");
 pub const Metal = @import("renderer/Metal.zig");
 pub const OpenGL = @import("renderer/OpenGL.zig");
+pub const Options = @import("renderer/Options.zig");
 pub const Thread = @import("renderer/Thread.zig");
 pub const State = @import("renderer/State.zig");
 

src/renderer/OpenGL.zig

@@ -77,6 +77,9 @@ background: terminal.color.RGB,
 /// True if the window is focused
 focused: bool,
 
+/// Padding options
+padding: renderer.Options.Padding,
+
 /// The raw structure that maps directly to the buffer sent to the vertex shader.
 /// This must be "extern" so that the field order is not reordered by the
 /// Zig compiler.
@@ -146,7 +149,7 @@ const GPUCellMode = enum(u8) {
     }
 };
 
-pub fn init(alloc: Allocator, font_group: *font.GroupCache) !OpenGL {
+pub fn init(alloc: Allocator, options: renderer.Options) !OpenGL {
     // Create the initial font shaper
     var shape_buf = try alloc.alloc(font.Shaper.Cell, 1);
     errdefer alloc.free(shape_buf);
@@ -157,8 +160,8 @@ pub fn init(alloc: Allocator, font_group: *font.GroupCache) !OpenGL {
     // Doesn't matter, any normal ASCII will do we're just trying to make
     // sure we use the regular font.
     const metrics = metrics: {
-        const index = (try font_group.indexForCodepoint(alloc, 'M', .regular, .text)).?;
+        const index = (try options.font_group.indexForCodepoint(alloc, 'M', .regular, .text)).?;
-        const face = try font_group.group.faceFromIndex(index);
+        const face = try options.font_group.group.faceFromIndex(index);
         break :metrics face.metrics;
     };
     log.debug("cell dimensions={}", .{metrics});
@@ -248,12 +251,12 @@ pub fn init(alloc: Allocator, font_group: *font.GroupCache) !OpenGL {
         try texbind.image2D(
             0,
             .Red,
-            @intCast(c_int, font_group.atlas_greyscale.size),
+            @intCast(c_int, options.font_group.atlas_greyscale.size),
-            @intCast(c_int, font_group.atlas_greyscale.size),
+            @intCast(c_int, options.font_group.atlas_greyscale.size),
             0,
             .Red,
             .UnsignedByte,
-            font_group.atlas_greyscale.data.ptr,
+            options.font_group.atlas_greyscale.data.ptr,
         );
     }
 
@@ -269,12 +272,12 @@ pub fn init(alloc: Allocator, font_group: *font.GroupCache) !OpenGL {
         try texbind.image2D(
             0,
             .RGBA,
-            @intCast(c_int, font_group.atlas_color.size),
+            @intCast(c_int, options.font_group.atlas_color.size),
-            @intCast(c_int, font_group.atlas_color.size),
+            @intCast(c_int, options.font_group.atlas_color.size),
             0,
             .BGRA,
             .UnsignedByte,
-            font_group.atlas_color.data.ptr,
+            options.font_group.atlas_color.data.ptr,
         );
     }
 
@@ -289,13 +292,14 @@ pub fn init(alloc: Allocator, font_group: *font.GroupCache) !OpenGL {
         .vbo = vbo,
         .texture = tex,
         .texture_color = tex_color,
-        .font_group = font_group,
+        .font_group = options.font_group,
         .font_shaper = shaper,
         .cursor_visible = true,
         .cursor_style = .box,
         .background = .{ .r = 0, .g = 0, .b = 0 },
         .foreground = .{ .r = 255, .g = 255, .b = 255 },
         .focused = true,
+        .padding = options.padding,
     };
 }
 
@@ -952,7 +956,9 @@ fn setScreenSize(self: *OpenGL, dim: renderer.ScreenSize) !void {
     // Determine if we need to pad the window. For "auto" padding, we take
     // the leftover amounts on the right/bottom that don't fit a full grid cell
     // and we split them equal across all boundaries.
-    const padding = renderer.Padding.balanced(dim, grid_size, self.cell_size);
+    const padding: renderer.Padding = if (self.padding.balance)
+        renderer.Padding.balanced(dim, grid_size, self.cell_size)
+    else .{};
     const padded_dim = dim.subPadding(padding);
 
     log.debug("screen size padded={} screen={} grid={} cell={}", .{ padded_dim, dim, grid_size, self.cell_size });

src/renderer/Options.zig

@@ -0,0 +1,21 @@
+//! The options that are used to configure a renderer.
+
+const font = @import("../font/main.zig");
+
+/// The font group that should be used.
+font_group: *font.GroupCache,
+
+/// Padding options for the viewport.
+padding: Padding,
+
+pub const Padding = struct {
+    // Explicit padding options, in pixels. The windowing thread is
+    // expected to convert points to pixels for a given DPI.
+    top: u32 = 0,
+    bottom: u32 = 0,
+    right: u32 = 0,
+    left: u32 = 0,
+
+    // Balance options
+    balance: bool = false,
+};

src/renderer/size.zig

@@ -78,10 +78,10 @@ pub const GridSize = struct {
 
 /// The padding to add to a screen.
 pub const Padding = struct {
-    top: f32,
+    top: f32 = 0,
-    bottom: f32,
+    bottom: f32 = 0,
-    right: f32,
+    right: f32 = 0,
-    left: f32,
+    left: f32 = 0,
 
     /// Returns padding that balances the whitespace around the screen
     /// for the given grid and cell sizes.