LibWeb: Extract CanvasDrawImage class from CRC2D

3 files changed, 97 insertions, 0 deletions

diff --git a/Userland/Libraries/LibWeb/HTML/Canvas/CanvasDrawImage.cpp b/Userland/Libraries/LibWeb/HTML/Canvas/CanvasDrawImage.cpp
new file mode 100644
index 0000000000..7e4620aa22
--- /dev/null
+++ b/Userland/Libraries/LibWeb/HTML/Canvas/CanvasDrawImage.cpp
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2022, Sam Atkins <atkinssj@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/HTML/Canvas/CanvasDrawImage.h>
+
+namespace Web::HTML {
+
+static void default_source_size(CanvasImageSource const& image, float& source_width, float& source_height)
+{
+    image.visit([&source_width, &source_height](auto const& source) {
+        if (source->bitmap()) {
+            source_width = source->bitmap()->width();
+            source_height = source->bitmap()->height();
+        } else {
+            source_width = source->width();
+            source_height = source->height();
+        }
+    });
+}
+
+DOM::ExceptionOr<void> CanvasDrawImage::draw_image(Web::HTML::CanvasImageSource const& image, float destination_x, float destination_y)
+{
+    // If not specified, the dw and dh arguments must default to the values of sw and sh, interpreted such that one CSS pixel in the image is treated as one unit in the output bitmap's coordinate space.
+    // If the sx, sy, sw, and sh arguments are omitted, then they must default to 0, 0, the image's intrinsic width in image pixels, and the image's intrinsic height in image pixels, respectively.
+    // If the image has no intrinsic dimensions, then the concrete object size must be used instead, as determined using the CSS "Concrete Object Size Resolution" algorithm, with the specified size having
+    // neither a definite width nor height, nor any additional constraints, the object's intrinsic properties being those of the image argument, and the default object size being the size of the output bitmap.
+    float source_width;
+    float source_height;
+    default_source_size(image, source_width, source_height);
+    return draw_image_internal(image, 0, 0, source_width, source_height, destination_x, destination_y, source_width, source_height);
+}
+
+DOM::ExceptionOr<void> CanvasDrawImage::draw_image(Web::HTML::CanvasImageSource const& image, float destination_x, float destination_y, float destination_width, float destination_height)
+{
+    // If the sx, sy, sw, and sh arguments are omitted, then they must default to 0, 0, the image's intrinsic width in image pixels, and the image's intrinsic height in image pixels, respectively.
+    // If the image has no intrinsic dimensions, then the concrete object size must be used instead, as determined using the CSS "Concrete Object Size Resolution" algorithm, with the specified size having
+    // neither a definite width nor height, nor any additional constraints, the object's intrinsic properties being those of the image argument, and the default object size being the size of the output bitmap.
+    float source_width;
+    float source_height;
+    default_source_size(image, source_width, source_height);
+    return draw_image_internal(image, 0, 0, source_width, source_height, destination_x, destination_y, destination_width, destination_height);
+}
+
+DOM::ExceptionOr<void> CanvasDrawImage::draw_image(Web::HTML::CanvasImageSource const& image, float source_x, float source_y, float source_width, float source_height, float destination_x, float destination_y, float destination_width, float destination_height)
+{
+    return draw_image_internal(image, source_x, source_y, source_width, source_height, destination_x, destination_y, destination_width, destination_height);
+}
+
+}
diff --git a/Userland/Libraries/LibWeb/HTML/Canvas/CanvasDrawImage.h b/Userland/Libraries/LibWeb/HTML/Canvas/CanvasDrawImage.h
new file mode 100644
index 0000000000..056620565c
--- /dev/null
+++ b/Userland/Libraries/LibWeb/HTML/Canvas/CanvasDrawImage.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2022, Sam Atkins <atkinssj@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/String.h>
+#include <LibWeb/DOM/ExceptionOr.h>
+#include <LibWeb/HTML/HTMLCanvasElement.h>
+#include <LibWeb/HTML/HTMLImageElement.h>
+
+namespace Web::HTML {
+
+// https://html.spec.whatwg.org/multipage/canvas.html#canvasimagesource
+// NOTE: This is the Variant created by the IDL wrapper generator, and needs to be updated accordingly.
+using CanvasImageSource = Variant<NonnullRefPtr<HTMLImageElement>, NonnullRefPtr<HTMLCanvasElement>>;
+
+// https://html.spec.whatwg.org/multipage/canvas.html#canvasdrawimage
+class CanvasDrawImage {
+public:
+    virtual ~CanvasDrawImage() = default;
+
+    DOM::ExceptionOr<void> draw_image(CanvasImageSource const&, float destination_x, float destination_y);
+    DOM::ExceptionOr<void> draw_image(CanvasImageSource const&, float destination_x, float destination_y, float destination_width, float destination_height);
+    DOM::ExceptionOr<void> draw_image(CanvasImageSource const&, float source_x, float source_y, float source_width, float source_height, float destination_x, float destination_y, float destination_width, float destination_height);
+
+    virtual DOM::ExceptionOr<void> draw_image_internal(CanvasImageSource const&, float source_x, float source_y, float source_width, float source_height, float destination_x, float destination_y, float destination_width, float destination_height) = 0;
+
+protected:
+    CanvasDrawImage() = default;
+};
+
+}
diff --git a/Userland/Libraries/LibWeb/HTML/Canvas/CanvasDrawImage.idl b/Userland/Libraries/LibWeb/HTML/Canvas/CanvasDrawImage.idl
new file mode 100644
index 0000000000..35dd06c2f4
--- /dev/null
+++ b/Userland/Libraries/LibWeb/HTML/Canvas/CanvasDrawImage.idl
@@ -0,0 +1,10 @@
+#import <HTML/HTMLCanvasElement.idl>
+#import <HTML/HTMLImageElement.idl>
+
+// https://html.spec.whatwg.org/multipage/canvas.html#canvasdrawimage
+interface mixin CanvasDrawImage {
+    // FIXME: These `image` params should be CanvasImageSource
+    undefined drawImage((HTMLImageElement or HTMLCanvasElement) image, unrestricted double dx, unrestricted double dy);
+    undefined drawImage((HTMLImageElement or HTMLCanvasElement) image, unrestricted double dx, unrestricted double dy, unrestricted double dw, unrestricted double dh);
+    undefined drawImage((HTMLImageElement or HTMLCanvasElement) image, unrestricted double sx, unrestricted double sy, unrestricted double sw, unrestricted double sh, unrestricted double dx, unrestricted double dy, unrestricted double dw, unrestricted double dh);
+};