Merge pull request #1553 from lightpanda-io/nikneym/image-data

Basic support for `ImageData`

src/browser/js/Context.zig

@@ -1045,6 +1045,12 @@ pub const FinalizerCallback = struct {
     }
 };
 
+/// Creates a new typed array. Memory is owned by JS context.
+/// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Typed_arrays
+pub fn createTypedArray(self: *Context, comptime array_type: js.ArrayType, size: usize) js.ArrayBufferRef(array_type) {
+    return .init(self.isolate, size);
+}
+
 // == Profiler ==
 pub fn startCpuProfiler(self: *Context) void {
     if (comptime !IS_DEBUG) {

src/browser/js/Local.zig

@@ -306,6 +306,14 @@ pub fn zigValueToJs(self: *const Local, value: anytype, comptime opts: CallOpts)
                 js.Value => return value,
                 js.Exception => return .{ .local = self, .handle = isolate.throwException(value.handle) },
 
+                js.ArrayBufferRef(.int8), js.ArrayBufferRef(.uint8), js.ArrayBufferRef(.uint8_clamped),
+                js.ArrayBufferRef(.int16), js.ArrayBufferRef(.uint16),
+                js.ArrayBufferRef(.int32), js.ArrayBufferRef(.uint32),
+                js.ArrayBufferRef(.float16), js.ArrayBufferRef(.float32), js.ArrayBufferRef(.float64),
+                => {
+                    return .{ .local = self, .handle = value.handle };
+                },
+
                 inline
                 js.Function,
                 js.Object,

src/browser/js/bridge.zig

@@ -864,4 +864,5 @@ pub const JsApis = flattenTypes(&.{
     @import("../webapi/canvas/WebGLRenderingContext.zig"),
     @import("../webapi/SubtleCrypto.zig"),
     @import("../webapi/Selection.zig"),
+    @import("../webapi/ImageData.zig"),
 });

src/browser/js/js.zig

@@ -77,14 +77,69 @@ pub const ArrayBuffer = struct {
     }
 };
 
-/// `ref` indicates bytes are not copied by `simpleZigValueToJs`;
-/// instead, `values` references an already allocated memory. Note that
-/// this variant assumes memory is (de)allocated by an arena allocator.
-///
-/// `copy` behaves the same as `TypedArray(T)`.
-pub fn Uint8ClampedArray(comptime state: enum(u1) { ref, copy }) type {
+pub const ArrayType = enum(u8) {
+    int8,
+    uint8,
+    uint8_clamped,
+    int16,
+    uint16,
+    int32,
+    uint32,
+    float16,
+    float32,
+    float64,
+};
+
+pub fn ArrayBufferRef(comptime kind: ArrayType) type {
     return struct {
-        values: if (state == .ref) []u8 else []const u8,
+        const Self = @This();
+
+        const BackingInt = switch (kind) {
+            .int8 => i8,
+            .uint8, .uint8_clamped => u8,
+            .int16 => i16,
+            .uint16 => u16,
+            .int32 => i32,
+            .uint32 => u32,
+            .float16 => f16,
+            .float32 => f32,
+            .float64 => f64,
+        };
+
+        handle: *const v8.Value,
+
+        pub fn init(isolate: Isolate, size: usize) Self {
+            const bits = switch (@typeInfo(BackingInt)) {
+                .int => |n| n.bits,
+                .float => |f| f.bits,
+                else => unreachable,
+            };
+
+            var array_buffer: *const v8.ArrayBuffer = undefined;
+            if (size == 0) {
+                array_buffer = v8.v8__ArrayBuffer__New(isolate.handle, 0).?;
+            } else {
+                const buffer_len = size * bits / 8;
+                const backing_store = v8.v8__ArrayBuffer__NewBackingStore(isolate.handle, buffer_len).?;
+                const backing_store_ptr = v8.v8__BackingStore__TO_SHARED_PTR(backing_store);
+                array_buffer = v8.v8__ArrayBuffer__New2(isolate.handle, &backing_store_ptr).?;
+            }
+
+            const handle: *const v8.Value = switch (comptime kind) {
+                .int8 => @ptrCast(v8.v8__Int8Array__New(array_buffer, 0, size).?),
+                .uint8 => @ptrCast(v8.v8__Uint8Array__New(array_buffer, 0, size).?),
+                .uint8_clamped => @ptrCast(v8.v8__Uint8ClampedArray__New(array_buffer, 0, size).?),
+                .int16 => @ptrCast(v8.v8__Int16Array__New(array_buffer, 0, size).?),
+                .uint16 => @ptrCast(v8.v8__Uint16Array__New(array_buffer, 0, size).?),
+                .int32 => @ptrCast(v8.v8__Int32Array__New(array_buffer, 0, size).?),
+                .uint32 => @ptrCast(v8.v8__Uint32Array__New(array_buffer, 0, size).?),
+                .float16 => @ptrCast(v8.v8__Float16Array__New(array_buffer, 0, size).?),
+                .float32 => @ptrCast(v8.v8__Float32Array__New(array_buffer, 0, size).?),
+                .float64 => @ptrCast(v8.v8__Float64Array__New(array_buffer, 0, size).?),
+            };
+
+            return .{ .handle = handle };
+        }
     };
 }
 
@@ -207,40 +262,6 @@ pub fn simpleZigValueToJs(isolate: Isolate, value: anytype, comptime fail: bool,
                     // but this can never be valid.
                     @compileError("Invalid TypeArray type: " ++ @typeName(value_type));
                 },
-                Uint8ClampedArray(.ref) => {
-                    const values = value.values;
-                    const len = values.len;
-                    var array_buffer: *const v8.ArrayBuffer = undefined;
-                    if (len == 0) {
-                        array_buffer = v8.v8__ArrayBuffer__New(isolate.handle, 0).?;
-                    } else {
-                        // `deleter` cannot be null.
-                        const empty_deleter = struct {
-                            fn deleter(_: ?*anyopaque, _: usize, _: ?*anyopaque) callconv(.c) void {}
-                        }.deleter;
-                        const backing_store = v8.v8__ArrayBuffer__NewBackingStore2(values.ptr, len, empty_deleter, null);
-                        const backing_store_ptr = v8.v8__BackingStore__TO_SHARED_PTR(backing_store);
-                        // Attach store to array buffer.
-                        array_buffer = v8.v8__ArrayBuffer__New2(isolate.handle, &backing_store_ptr).?;
-                    }
-                    return @ptrCast(v8.v8__Uint8ClampedArray__New(array_buffer, 0, len));
-                },
-                Uint8ClampedArray(.copy) => {
-                    const values = value.values;
-                    const len = values.len;
-                    var array_buffer: *const v8.ArrayBuffer = undefined;
-                    if (len == 0) {
-                        array_buffer = v8.v8__ArrayBuffer__New(isolate.handle, 0).?;
-                    } else {
-                        const backing_store = v8.v8__ArrayBuffer__NewBackingStore(isolate.handle, len);
-                        const data: [*]u8 = @ptrCast(@alignCast(v8.v8__BackingStore__Data(backing_store)));
-                        @memcpy(data[0..len], @as([]const u8, @ptrCast(values))[0..len]);
-                        const backing_store_ptr = v8.v8__BackingStore__TO_SHARED_PTR(backing_store);
-                        // Attach store to array buffer.
-                        array_buffer = v8.v8__ArrayBuffer__New2(isolate.handle, &backing_store_ptr).?;
-                    }
-                    return @ptrCast(v8.v8__Uint8ClampedArray__New(array_buffer, 0, len));
-                },
                 inline String, BigInt, Integer, Number, Value, Object => return value.handle,
                 else => {},
             }

src/browser/tests/image_data.html

@@ -0,0 +1,75 @@
+<!DOCTYPE html>
+<script src="testing.js"></script>
+
+<script id=constructor-basic>
+  {
+    const img = new ImageData(10, 20);
+    testing.expectEqual(10, img.width);
+    testing.expectEqual(20, img.height);
+    testing.expectEqual("srgb", img.colorSpace);
+    testing.expectEqual("rgba-unorm8", img.pixelFormat);
+  }
+</script>
+
+<script id=data-property>
+  {
+    const img = new ImageData(2, 3);
+    const data = img.data;
+    testing.expectEqual(true, data instanceof Uint8ClampedArray);
+    // 2 * 3 * 4 (RGBA) = 24 bytes
+    testing.expectEqual(24, data.length);
+  }
+</script>
+
+<script id=data-initialized-to-zero>
+  {
+    const img = new ImageData(2, 2);
+    const data = img.data;
+    for (let i = 0; i < data.length; i++) {
+      testing.expectEqual(0, data[i]);
+    }
+  }
+</script>
+
+<script id=data-mutability>
+  {
+    const img = new ImageData(1, 1);
+    const data = img.data;
+    // Set pixel to red (RGBA)
+    data[0] = 255;
+    data[1] = 0;
+    data[2] = 0;
+    data[3] = 255;
+
+    // Read back through the same accessor
+    const data2 = img.data;
+    testing.expectEqual(255, data2[0]);
+    testing.expectEqual(0, data2[1]);
+    testing.expectEqual(0, data2[2]);
+    testing.expectEqual(255, data2[3]);
+  }
+</script>
+
+<script id=constructor-with-settings>
+  {
+    const img = new ImageData(5, 5, { colorSpace: "srgb" });
+    testing.expectEqual(5, img.width);
+    testing.expectEqual(5, img.height);
+    testing.expectEqual("srgb", img.colorSpace);
+  }
+</script>
+
+<script id=constructor-invalid-colorspace>
+  testing.expectError("TypeError", () => {
+    new ImageData(5, 5, { colorSpace: "display-p3" });
+  });
+</script>
+
+<script id=single-pixel>
+  {
+    const img = new ImageData(1, 1);
+    testing.expectEqual(4, img.data.length);
+    testing.expectEqual(1, img.width);
+    testing.expectEqual(1, img.height);
+  }
+</script>

src/browser/webapi/ImageData.zig

@@ -0,0 +1,122 @@
+// Copyright (C) 2023-2026 Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const String = @import("../../string.zig").String;
+const log = @import("../../log.zig");
+
+const js = @import("../js/js.zig");
+const color = @import("../color.zig");
+const Page = @import("../Page.zig");
+
+/// https://developer.mozilla.org/en-US/docs/Web/API/ImageData/ImageData
+const ImageData = @This();
+_width: u32,
+_height: u32,
+_data: js.ArrayBufferRef(.uint8_clamped),
+
+pub const ConstructorSettings = struct {
+    /// Specifies the color space of the image data.
+    /// Can be set to "srgb" for the sRGB color space or "display-p3" for the display-p3 color space.
+    colorSpace: String = .wrap("srgb"),
+    /// Specifies the pixel format.
+    /// https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/createImageData#pixelformat
+    pixelFormat: String = .wrap("rgba-unorm8"),
+};
+
+/// This has many constructors:
+///
+/// ```js
+/// new ImageData(width, height)
+/// new ImageData(width, height, settings)
+///
+/// new ImageData(dataArray, width)
+/// new ImageData(dataArray, width, height)
+/// new ImageData(dataArray, width, height, settings)
+/// ```
+///
+/// We currently support only the first 2.
+pub fn constructor(
+    width: u32,
+    height: u32,
+    maybe_settings: ?ConstructorSettings,
+    page: *Page,
+) !*ImageData {
+    if (width == 0 or height == 0) {
+        return error.IndexSizeError;
+    }
+
+    const settings: ConstructorSettings = maybe_settings orelse .{};
+    if (settings.colorSpace.eql(comptime .wrap("srgb")) == false) {
+        return error.TypeError;
+    }
+    if (settings.pixelFormat.eql(comptime .wrap("rgba-unorm8")) == false) {
+        return error.TypeError;
+    }
+
+    const size = width * height * 4;
+    return page._factory.create(ImageData{
+        ._width = width,
+        ._height = height,
+        ._data = page.js.createTypedArray(.uint8_clamped, size),
+    });
+}
+
+pub fn getWidth(self: *const ImageData) u32 {
+    return self._width;
+}
+
+pub fn getHeight(self: *const ImageData) u32 {
+    return self._height;
+}
+
+pub fn getPixelFormat(_: *const ImageData) String {
+    return comptime .wrap("rgba-unorm8");
+}
+
+pub fn getColorSpace(_: *const ImageData) String {
+    return comptime .wrap("srgb");
+}
+
+pub fn getData(self: *const ImageData) js.ArrayBufferRef(.uint8_clamped) {
+    return self._data;
+}
+
+pub const JsApi = struct {
+    pub const bridge = js.Bridge(ImageData);
+
+    pub const Meta = struct {
+        pub const name = "ImageData";
+        pub const prototype_chain = bridge.prototypeChain();
+        pub var class_id: bridge.ClassId = undefined;
+    };
+
+    pub const constructor = bridge.constructor(ImageData.constructor, .{ .dom_exception = true });
+
+    pub const width = bridge.accessor(ImageData.getWidth, null, .{});
+    pub const height = bridge.accessor(ImageData.getHeight, null, .{});
+    pub const pixelFormat = bridge.accessor(ImageData.getPixelFormat, null, .{});
+    pub const colorSpace = bridge.accessor(ImageData.getColorSpace, null, .{});
+    pub const data = bridge.accessor(ImageData.getData, null, .{});
+};
+
+const testing = @import("../../testing.zig");
+test "WebApi: ImageData" {
+    try testing.htmlRunner("image_data.html", .{});
+}