mirrors/ladybird
0
0
Fork 0
mirror of https://github.com/LadybirdBrowser/ladybird.git synced 2025-07-15 05:22:04 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 9

LibWeb: Don't crash when setting offscreen canvas size to 0

Browse source 
Previously, this would crash because `Gfx::Bitmap` can't have a zero
size.
This commit is contained in:
Tim Ledbetter 2025-07-01 01:19:08 +01:00 • committed by Sam Atkins
parent f882c446cb
commit 5413716802
Notes: github-actions[bot] 2025-07-04 15:11:48 +00:00
5 changed files with 78 additions and 18 deletions
Download patch file Download diff file Expand all files Collapse all files

45
Libraries/LibWeb/HTML/OffscreenCanvas.cpp
View file

@ -31,16 +31,17 @@ WebIDL::ExceptionOr<GC::Ref<OffscreenCanvas>> OffscreenCanvas::construct_impl(
WebIDL::UnsignedLong width,
WebIDL::UnsignedLong height)
{
RefPtr<Gfx::Bitmap> bitmap;
if (width > 0 && height > 0) {
// The new OffscreenCanvas(width, height) constructor steps are:
auto bitmap_or_error = Gfx::Bitmap::create(Gfx::BitmapFormat::RGBA8888, Gfx::IntSize { width, height });
// The new OffscreenCanvas(width, height) constructor steps are:
auto bitmap_or_error = Gfx::Bitmap::create(Gfx::BitmapFormat::RGBA8888, Gfx::IntSize { width, height });
if (bitmap_or_error.is_error()) {
return WebIDL::InvalidStateError::create(realm, MUST(String::formatted("Error in allocating bitmap: {}", bitmap_or_error.error())));
if (bitmap_or_error.is_error()) {
return WebIDL::InvalidStateError::create(realm, MUST(String::formatted("Error in allocating bitmap: {}", bitmap_or_error.error())));
}
bitmap = bitmap_or_error.release_value();
}
auto bitmap = bitmap_or_error.release_value();
// 1. Initialize the bitmap of this to a rectangular array of transparent black pixels of the dimensions specified by width and height.
// noop, the pixel value to set is equal to 0x00000000, which the bitmap already contains
@ -71,7 +72,7 @@ WebIDL::ExceptionOr<GC::Ref<OffscreenCanvas>> OffscreenCanvas::construct_impl(
}
// https://html.spec.whatwg.org/multipage/canvas.html#dom-offscreencanvas
OffscreenCanvas::OffscreenCanvas(JS::Realm& realm, NonnullRefPtr<Gfx::Bitmap> bitmap)
OffscreenCanvas::OffscreenCanvas(JS::Realm& realm, RefPtr<Gfx::Bitmap> bitmap)
: EventTarget(realm)
, m_bitmap { move(bitmap) }
{
@ -102,11 +103,17 @@ HTML::TransferType OffscreenCanvas::primary_interface() const
WebIDL::UnsignedLong OffscreenCanvas::width() const
{
if (!m_bitmap)
return 0;
return m_bitmap->size().width();
}
WebIDL::UnsignedLong OffscreenCanvas::height() const
{
if (!m_bitmap)
return 0;
return m_bitmap->size().height();
}
@ -129,7 +136,11 @@ void OffscreenCanvas::reset_context_to_default_state()
void OffscreenCanvas::set_new_bitmap_size(Gfx::IntSize new_size)
{
m_bitmap = MUST(Gfx::Bitmap::create(Gfx::BitmapFormat::RGBA8888, Gfx::IntSize { new_size.width(), new_size.height() }));
if (new_size.width() == 0 || new_size.height() == 0)
m_bitmap = nullptr;
else {
m_bitmap = MUST(Gfx::Bitmap::create(Gfx::BitmapFormat::RGBA8888, Gfx::IntSize { new_size.width(), new_size.height() }));
}
m_context.visit(
[&](GC::Ref<OffscreenCanvasRenderingContext2D>& context) {
@ -145,7 +156,7 @@ void OffscreenCanvas::set_new_bitmap_size(Gfx::IntSize new_size)
// Do nothing.
});
}
NonnullRefPtr<Gfx::Bitmap> OffscreenCanvas::bitmap() const
RefPtr<Gfx::Bitmap> OffscreenCanvas::bitmap() const
{
return m_bitmap;
}
@ -171,6 +182,8 @@ WebIDL::ExceptionOr<void> OffscreenCanvas::set_height(WebIDL::UnsignedLong value
Gfx::IntSize OffscreenCanvas::bitmap_size_for_canvas() const
{
if (!m_bitmap)
return { 0, 0 };
return m_bitmap->size();
}
@ -224,10 +237,14 @@ WebIDL::ExceptionOr<GC::Ref<ImageBitmap>> OffscreenCanvas::transfer_to_image_bit
auto image = ImageBitmap::create(realm());
image->set_bitmap(m_bitmap);
// 4. Set this OffscreenCanvas object 's bitmap to reference a newly created bitmap of the same dimensions and color space as the previous bitmap, and with its pixels initialized to transparent black, or opaque black if the rendering context' s alpha is false.
// 4. Set this OffscreenCanvas object's bitmap to reference a newly created bitmap of the same dimensions and color space as the previous bitmap, and with its pixels initialized to transparent black, or opaque black if the rendering context' s alpha is false.
// FIXME: implement the checking of the alpha from the context
auto size = bitmap_size_for_canvas();
m_bitmap = MUST(Gfx::Bitmap::create(Gfx::BitmapFormat::RGBA8888, size));
if (size.is_empty()) {
m_bitmap = nullptr;
} else {
m_bitmap = MUST(Gfx::Bitmap::create(Gfx::BitmapFormat::RGBA8888, size));
}
// 5. Return image.
return image;
@ -262,7 +279,9 @@ GC::Ref<WebIDL::Promise> OffscreenCanvas::convert_to_blob(Optional<ImageEncodeOp
}
// 4. Let bitmap be a copy of this OffscreenCanvas object's bitmap.
auto bitmap = MUST(m_bitmap->clone());
RefPtr<Gfx::Bitmap> bitmap;
if (m_bitmap)
bitmap = MUST(m_bitmap->clone());
// 5. Let result be a new promise object.
auto result_promise = WebIDL::create_promise(realm());