From c377e19bd0c7d9f4acdc6e859001a61e311805ba Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Sun, 28 Aug 2022 12:11:26 -0700
Subject: [PATCH] pkg/harfbuzz: shape

---
 pkg/harfbuzz/common.zig | 29 +++++++++++++++++++++++++++++
 pkg/harfbuzz/main.zig   |  1 +
 pkg/harfbuzz/shape.zig  | 19 +++++++++++++++++++
 3 files changed, 49 insertions(+)
 create mode 100644 pkg/harfbuzz/shape.zig

diff --git a/pkg/harfbuzz/common.zig b/pkg/harfbuzz/common.zig
index 8a3589fbd..84b4d000f 100644
--- a/pkg/harfbuzz/common.zig
+++ b/pkg/harfbuzz/common.zig
@@ -214,3 +214,32 @@ pub const Language = struct {
         return .{ .handle = c.hb_language_get_default() };
     }
 };
+
+/// The hb_feature_t is the structure that holds information about requested
+/// feature application. The feature will be applied with the given value to
+/// all glyphs which are in clusters between start (inclusive) and end
+/// (exclusive). Setting start to HB_FEATURE_GLOBAL_START and end to
+/// HB_FEATURE_GLOBAL_END specifies that the feature always applies to the
+/// entire buffer.
+pub const Feature = extern struct {
+    tag: c.hb_tag_t,
+    value: u32,
+    start: c_uint,
+    end: c_uint,
+
+    pub fn fromString(str: []const u8) ?Feature {
+        var f: Feature = undefined;
+        return if (c.hb_feature_from_string(
+            str.ptr,
+            @intCast(c_int, str.len),
+            &f,
+        ) > 1)
+            f
+        else
+            null;
+    }
+
+    pub fn toString(self: *Feature, buf: []u8) void {
+        c.hb_feature_to_string(self, buf.ptr, @intCast(c_uint, buf.len));
+    }
+};
diff --git a/pkg/harfbuzz/main.zig b/pkg/harfbuzz/main.zig
index c1b7c2da9..85df31b30 100644
--- a/pkg/harfbuzz/main.zig
+++ b/pkg/harfbuzz/main.zig
@@ -5,6 +5,7 @@ pub usingnamespace @import("common.zig");
 pub usingnamespace @import("errors.zig");
 pub usingnamespace @import("face.zig");
 pub usingnamespace @import("font.zig");
+pub usingnamespace @import("shape.zig");
 pub usingnamespace @import("version.zig");
 pub const Freetype = @import("freetype.zig");
 
diff --git a/pkg/harfbuzz/shape.zig b/pkg/harfbuzz/shape.zig
new file mode 100644
index 000000000..260fbc85d
--- /dev/null
+++ b/pkg/harfbuzz/shape.zig
@@ -0,0 +1,19 @@
+const std = @import("std");
+const c = @import("c.zig");
+const Font = @import("font.zig").Font;
+const Buffer = @import("buffer.zig").Buffer;
+const Feature = @import("common.zig").Feature;
+
+/// Shapes buffer using font turning its Unicode characters content to
+/// positioned glyphs. If features is not NULL, it will be used to control
+/// the features applied during shaping. If two features have the same tag
+/// but overlapping ranges the value of the feature with the higher index
+/// takes precedence.
+pub fn shape(font: Font, buf: Buffer, features: ?[]const Feature) void {
+    c.hb_shape(
+        font.handle,
+        buf.handle,
+        if (features) |f| @ptrCast([*]const c.hb_feature_t, f.ptr) else null,
+        if (features) |f| @intCast(c_uint, f.len) else 0,
+    );
+}