From 62990bb33e8c87938f3795a8f4123c59dd53b047 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Mon, 5 Dec 2022 20:52:03 -0800
Subject: [PATCH] font: Group is now wasm-compatible

---
 example/app.ts     | 19 ++++++++---
 src/font/Group.zig | 81 +++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 88 insertions(+), 12 deletions(-)

diff --git a/example/app.ts b/example/app.ts
index 5dcd949be..85eee4d5b 100644
--- a/example/app.ts
+++ b/example/app.ts
@@ -32,6 +32,11 @@ fetch(url.href).then(response =>
     deferred_face_free,
     deferred_face_load,
     deferred_face_face,
+    group_new,
+    group_free,
+    group_add_face,
+    group_index_for_codepoint,
+    group_render_glyph,
     atlas_new,
     atlas_free,
     atlas_debug_canvas,
@@ -53,22 +58,28 @@ fetch(url.href).then(response =>
 
   // Initialize our deferred face
   const df = deferred_face_new(font_ptr, font.byteLength);
-  deferred_face_load(df, 72 /* size */);
-  const face = deferred_face_face(df);
+  //deferred_face_load(df, 72 /* size */);
+  //const face = deferred_face_face(df);
 
   // Initialize our font face
   //const face = face_new(font_ptr, font.byteLength, 72 /* size in px */);
   free(font_ptr);
 
+  // Create our group
+  const group = group_new(72 /* size */);
+  group_add_face(group, 0, df);
+
   // Render a glyph
   for (let i = 33; i <= 126; i++) {
-    face_render_glyph(face, atlas, i);
+    const font_idx = group_index_for_codepoint(group, i, 0, -1);
+    group_render_glyph(group, atlas, font_idx, i, 0);
+    //face_render_glyph(face, atlas, i);
   }
   //face_render_glyph(face, atlas, "橋".codePointAt(0));
   //face_render_glyph(face, atlas, "p".codePointAt(0));
 
   // Debug our canvas
-  face_debug_canvas(face);
+  //face_debug_canvas(face);
 
   // Debug our atlas canvas
   const id = atlas_debug_canvas(atlas);
diff --git a/src/font/Group.zig b/src/font/Group.zig
index 92fbf7100..dbe9cd499 100644
--- a/src/font/Group.zig
+++ b/src/font/Group.zig
@@ -119,7 +119,7 @@ pub fn setSize(self: *Group, size: font.face.DesiredSize) !void {
 }
 
 /// This represents a specific font in the group.
-pub const FontIndex = packed struct {
+pub const FontIndex = packed struct(u8) {
     /// The number of bits we use for the index.
     const idx_bits = 8 - @typeInfo(@typeInfo(Style).Enum.tag_type).Int.bits;
     pub const IndexInt = @Type(.{ .Int = .{ .signedness = .unsigned, .bits = idx_bits } });
@@ -272,13 +272,16 @@ pub fn renderGlyph(
     max_height: ?u16,
 ) !Glyph {
     // Special-case fonts are rendered directly.
-    if (index.special()) |sp| switch (sp) {
-        .sprite => return try self.sprite.?.renderGlyph(
-            alloc,
-            atlas,
-            glyph_index,
-        ),
-    };
+    // TODO: web_canvas
+    if (options.backend != .web_canvas) {
+        if (index.special()) |sp| switch (sp) {
+            .sprite => return try self.sprite.?.renderGlyph(
+                alloc,
+                atlas,
+                glyph_index,
+            ),
+        };
+    }
 
     const face = &self.faces.get(index.style).items[@intCast(usize, index.idx)];
     try face.load(self.lib, self.size);
@@ -303,6 +306,68 @@ pub const Wasm = struct {
         result.* = group;
         return result;
     }
+
+    export fn group_free(ptr: ?*Group) void {
+        if (ptr) |v| {
+            v.deinit();
+            alloc.destroy(v);
+        }
+    }
+
+    export fn group_add_face(self: *Group, style: u16, face: *font.DeferredFace) void {
+        return self.addFace(alloc, @intToEnum(Style, style), face.*) catch |err| {
+            log.warn("error adding face to group err={}", .{err});
+            return;
+        };
+    }
+
+    export fn group_set_size(self: *Group, size: u16) void {
+        return self.setSize(.{ .points = size }) catch |err| {
+            log.warn("error setting group size err={}", .{err});
+            return;
+        };
+    }
+
+    /// Presentation is negative for doesn't matter.
+    export fn group_index_for_codepoint(self: *Group, cp: u32, style: u16, p: i16) i16 {
+        const presentation = if (p < 0) null else @intToEnum(Presentation, p);
+        const idx = self.indexForCodepoint(
+            cp,
+            @intToEnum(Style, style),
+            presentation,
+        ) orelse return -1;
+        return @intCast(i16, @bitCast(u8, idx));
+    }
+
+    export fn group_render_glyph(
+        self: *Group,
+        atlas: *font.Atlas,
+        idx: i16,
+        cp: u32,
+        max_height: u16,
+    ) ?*Glyph {
+        return group_render_glyph_(self, atlas, idx, cp, max_height) catch |err| {
+            log.warn("error rendering group glyph err={}", .{err});
+            return null;
+        };
+    }
+
+    fn group_render_glyph_(
+        self: *Group,
+        atlas: *font.Atlas,
+        idx_: i16,
+        cp: u32,
+        max_height_: u16,
+    ) !*Glyph {
+        const idx = @bitCast(FontIndex, @intCast(u8, idx_));
+        const max_height = if (max_height_ <= 0) null else max_height_;
+        const glyph = try self.renderGlyph(alloc, atlas, idx, cp, max_height);
+
+        var result = try alloc.create(Glyph);
+        errdefer alloc.destroy(result);
+        result.* = glyph;
+        return result;
+    }
 };
 
 test {