Merge pull request #671 from mitchellh/sprite-width

Fix cursor width, underline width with wide chars

src/font/Group.zig

@@ -515,6 +515,7 @@ pub fn renderGlyph(
             alloc,
             atlas,
             glyph_index,
+            opts,
         ),
     };
 

src/font/GroupCache.zig

@@ -41,6 +41,7 @@ const CodepointKey = struct {
 const GlyphKey = struct {
     index: Group.FontIndex,
     glyph: u32,
+    opts: font.face.RenderOptions,
 };
 
 /// The GroupCache takes ownership of Group and will free it.
@@ -124,7 +125,7 @@ pub fn renderGlyph(
     glyph_index: u32,
     opts: font.face.RenderOptions,
 ) !Glyph {
-    const key: GlyphKey = .{ .index = index, .glyph = glyph_index };
+    const key: GlyphKey = .{ .index = index, .glyph = glyph_index, .opts = opts };
     const gop = try self.glyphs.getOrPut(alloc, key);
 
     // If it is in the cache, use it.

src/font/face.zig

@@ -76,6 +76,10 @@ pub const RenderOptions = struct {
     /// is typically naive, but ultimately up to the rasterizer.
     max_height: ?u16 = null,
 
+    /// The number of grid cells this glyph will take up. This can be used
+    /// optionally by the rasterizer to better layout the glyph.
+    cell_width: ?u2 = null,
+
     /// Thicken the glyph. This draws the glyph with a thicker stroke width.
     /// This is purely an aesthetic setting.
     ///

src/font/sprite/Face.zig

@@ -49,6 +49,7 @@ pub fn renderGlyph(
     alloc: Allocator,
     atlas: *font.Atlas,
     cp: u32,
+    opts: font.face.RenderOptions,
 ) !font.Glyph {
     if (std.debug.runtime_safety) {
         if (!self.hasCodepoint(cp, null)) {
@@ -57,11 +58,17 @@ pub fn renderGlyph(
         }
     }
 
+    // We adjust our sprite width based on the cell width.
+    const width = switch (opts.cell_width orelse 1) {
+        0, 1 => self.width,
+        else => |width| self.width * width,
+    };
+
     // Safe to ".?" because of the above assertion.
     return switch (Kind.init(cp).?) {
         .box => box: {
             const f: Box = .{
-                .width = self.width,
+                .width = width,
                 .height = self.height,
                 .thickness = self.thickness,
             };
@@ -73,7 +80,7 @@ pub fn renderGlyph(
             alloc,
             atlas,
             @enumFromInt(cp),
-            self.width,
+            width,
             self.height,
             self.underline_position,
             self.thickness,

src/renderer/Metal.zig

@@ -1364,7 +1364,7 @@ pub fn updateCell(
             self.alloc,
             font.sprite_index,
             @intFromEnum(sprite),
-            .{},
+            .{ .cell_width = if (cell.attrs.wide) 2 else 1 },
         );
 
         const color = if (cell.attrs.underline_color) cell.underline_fg else colors.fg;
@@ -1397,12 +1397,26 @@ fn addCursor(
     screen: *terminal.Screen,
     cursor_style: renderer.CursorStyle,
 ) ?*const mtl_shaders.Cell {
-    // Add the cursor
+    // Add the cursor. We render the cursor over the wide character if
+    // we're on the wide characer tail.
+    const cell, const x = cell: {
+        // The cursor goes over the screen cursor position.
         const cell = screen.getCell(
             .active,
             screen.cursor.y,
             screen.cursor.x,
         );
+        if (!cell.attrs.wide_spacer_tail or screen.cursor.x == 0)
+            break :cell .{ cell, screen.cursor.x };
+
+        // If we're part of a wide character, we move the cursor back to
+        // the actual character.
+        break :cell .{ screen.getCell(
+            .active,
+            screen.cursor.y,
+            screen.cursor.x - 1,
+        ), screen.cursor.x - 1 };
+    };
 
     const color = self.config.cursor_color orelse terminal.color.RGB{
         .r = 0xFF,
@@ -1421,7 +1435,7 @@ fn addCursor(
         self.alloc,
         font.sprite_index,
         @intFromEnum(sprite),
-        .{},
+        .{ .cell_width = if (cell.attrs.wide) 2 else 1 },
     ) catch |err| {
         log.warn("error rendering cursor glyph err={}", .{err});
         return null;
@@ -1430,7 +1444,7 @@ fn addCursor(
     self.cells.appendAssumeCapacity(.{
         .mode = .fg,
         .grid_pos = .{
-            @as(f32, @floatFromInt(screen.cursor.x)),
+            @as(f32, @floatFromInt(x)),
             @as(f32, @floatFromInt(screen.cursor.y)),
         },
         .cell_width = if (cell.attrs.wide) 2 else 1,

src/renderer/OpenGL.zig

@@ -848,12 +848,26 @@ fn addCursor(
     screen: *terminal.Screen,
     cursor_style: renderer.CursorStyle,
 ) ?*const GPUCell {
-    // Add the cursor
+    // Add the cursor. We render the cursor over the wide character if
+    // we're on the wide characer tail.
+    const cell, const x = cell: {
+        // The cursor goes over the screen cursor position.
         const cell = screen.getCell(
             .active,
             screen.cursor.y,
             screen.cursor.x,
         );
+        if (!cell.attrs.wide_spacer_tail or screen.cursor.x == 0)
+            break :cell .{ cell, screen.cursor.x };
+
+        // If we're part of a wide character, we move the cursor back to
+        // the actual character.
+        break :cell .{ screen.getCell(
+            .active,
+            screen.cursor.y,
+            screen.cursor.x - 1,
+        ), screen.cursor.x - 1 };
+    };
 
     const color = self.config.cursor_color orelse terminal.color.RGB{
         .r = 0xFF,
@@ -872,7 +886,7 @@ fn addCursor(
         self.alloc,
         font.sprite_index,
         @intFromEnum(sprite),
-        .{},
+        .{ .cell_width = if (cell.attrs.wide) 2 else 1 },
     ) catch |err| {
         log.warn("error rendering cursor glyph err={}", .{err});
         return null;
@@ -880,7 +894,7 @@ fn addCursor(
 
     self.cells.appendAssumeCapacity(.{
         .mode = .fg,
-        .grid_col = @intCast(screen.cursor.x),
+        .grid_col = @intCast(x),
         .grid_row = @intCast(screen.cursor.y),
         .grid_width = if (cell.attrs.wide) 2 else 1,
         .fg_r = color.r,
@@ -1136,7 +1150,7 @@ pub fn updateCell(
             self.alloc,
             font.sprite_index,
             @intFromEnum(sprite),
-            .{},
+            .{ .cell_width = if (cell.attrs.wide) 2 else 1 },
         );
 
         const color = if (cell.attrs.underline_color) cell.underline_fg else colors.fg;

src/terminal/Terminal.zig

@@ -821,9 +821,10 @@ fn printCell(self: *Terminal, unmapped_c: u21) *Screen.Cell {
         const x = self.screen.cursor.x - 1;
 
         const wide_cell = row.getCellPtr(x);
+        wide_cell.char = 0;
         wide_cell.attrs.wide = false;
 
-        if (self.screen.cursor.x <= 1) {
+        if (self.screen.cursor.y > 0 and self.screen.cursor.x <= 1) {
             self.clearWideSpacerHead();
         }
     }
@@ -2013,6 +2014,47 @@ test "Terminal: print over wide char at 0,0" {
 
     try testing.expectEqual(@as(usize, 0), t.screen.cursor.y);
     try testing.expectEqual(@as(usize, 1), t.screen.cursor.x);
+
+    const row = t.screen.getRow(.{ .screen = 0 });
+    {
+        const cell = row.getCell(0);
+        try testing.expectEqual(@as(u32, 'A'), cell.char);
+        try testing.expect(!cell.attrs.wide);
+        try testing.expectEqual(@as(usize, 1), row.codepointLen(0));
+    }
+    {
+        const cell = row.getCell(1);
+        try testing.expect(!cell.attrs.wide_spacer_tail);
+    }
+}
+
+test "Terminal: print over wide spacer tail" {
+    var t = try init(testing.allocator, 5, 5);
+    defer t.deinit(testing.allocator);
+
+    try t.print('橋');
+    t.setCursorPos(1, 2);
+    try t.print('X');
+
+    {
+        var str = try t.plainString(testing.allocator);
+        defer testing.allocator.free(str);
+        try testing.expectEqualStrings(" X", str);
+    }
+
+    const row = t.screen.getRow(.{ .screen = 0 });
+    {
+        const cell = row.getCell(0);
+        try testing.expectEqual(@as(u32, 0), cell.char);
+        try testing.expect(!cell.attrs.wide);
+        try testing.expectEqual(@as(usize, 1), row.codepointLen(0));
+    }
+    {
+        const cell = row.getCell(1);
+        try testing.expectEqual(@as(u32, 'X'), cell.char);
+        try testing.expect(!cell.attrs.wide_spacer_tail);
+        try testing.expectEqual(@as(usize, 1), row.codepointLen(1));
+    }
 }
 
 test "Terminal: print multicodepoint grapheme, disabled mode 2027" {