BitmapSurface

#include <Ultralight/platform/Surface.h>

Overview

The default surface implementation, backed by a bitmap.

This is automatically provided by the library when you call Renderer::Create() without defining a custom SurfaceFactory.

This implementation uses a Bitmap to store pixel data (retrieve it via BitmapSurface::bitmap()).

Inheritance diagram for BitmapSurface:

Public Member Functions
virtual uint32_t	width () const override
	Width (in pixels).
virtual uint32_t	height () const override
	Height (in pixels).
virtual uint32_t	row_bytes () const override
	Number of bytes between rows (usually width * 4).
virtual size_t	size () const override
	Size in bytes.
virtual void *	LockPixels () override
	Lock the pixel buffer and get a pointer to the beginning of the data for reading/writing.
virtual void	UnlockPixels () override
	Unlock the pixel buffer.
virtual void	Resize (uint32_t width, uint32_t height) override
	Resize the pixel buffer to a certain width and height (both in pixels).
virtual bool	Scroll (const IntRect &rect, int dx, int dy) override
	Shift a rectangle of pixels by an offset.
RefPtr< Bitmap >	bitmap ()
	Get the underlying Bitmap.
Public Member Functions inherited from Surface
virtual	~Surface ()
LockedPixels< Surface * >	LockPixelsSafe ()
	Lock the pixel buffer for reading/writing (safe version, automatically unlocks).
virtual void	set_dirty_bounds (const IntRect &bounds)
	Add a rectangle to the dirty area.
virtual IntRect	dirty_bounds () const
	Get the dirty bounds.
virtual void	ClearDirtyBounds ()
	Clear the dirty bounds.
uint32_t	dirty_rect_count () const
	Get the number of dirty rectangles (0 when nothing has been painted since the last clear).
IntRect	dirty_rect (uint32_t index) const
	Get a dirty rectangle by index.

Protected Member Functions
	BitmapSurface (uint32_t width, uint32_t height)
virtual	~BitmapSurface ()
	BitmapSurface (const BitmapSurface &)=delete
void	operator= (const BitmapSurface &)=delete
Protected Member Functions inherited from Surface
	Surface ()

Protected Attributes
void *	impl_
Protected Attributes inherited from Surface
IntRect	dirty_bounds_
IntRect	dirty_rects_ [kMaxDirtyRects]
uint32_t	dirty_rect_count_ = 0

Friends
class	BitmapSurfaceFactory

Additional Inherited Members
Static Public Member Functions inherited from Surface
static void	ShiftPixels (void *pixels, uint32_t row_bytes, const IntRect &rect, int dx, int dy)
	Shift a rectangle of 32-bit pixels in place.
Static Public Attributes inherited from Surface
static constexpr uint32_t	kMaxDirtyRects = 8
	The most dirty rectangles the library keeps apart before merging them.

Constructor & Destructor Documentation

BitmapSurface() [1/2]

BitmapSurface ( uint32_t width, uint32_t height )

protected

~BitmapSurface()

virtual ~BitmapSurface ( )

protectedvirtual

BitmapSurface() [2/2]

BitmapSurface ( const BitmapSurface & )

protecteddelete

Member Function Documentation

bitmap()

RefPtr< Bitmap > bitmap

(

)

Get the underlying Bitmap.

height()

virtual uint32_t height ( ) const

overridevirtual

Height (in pixels).

Implements Surface.

LockPixels()

virtual void * LockPixels ( )

overridevirtual

Lock the pixel buffer and get a pointer to the beginning of the data for reading/writing.

Note

Native pixel format is premultiplied BGRA 32-bit (8 bits per channel).

Returns

Returns a pointer to the beginning of the locked pixel buffer. The buffer remains valid until UnlockPixels() is called.

Implements Surface.

operator=()

void operator= ( const BitmapSurface & )

protecteddelete

Resize()

virtual void Resize ( uint32_t width, uint32_t height )

overridevirtual

Resize the pixel buffer to a certain width and height (both in pixels).

This should never be called while pixels are locked.

Implements Surface.

row_bytes()

virtual uint32_t row_bytes ( ) const

overridevirtual

Number of bytes between rows (usually width * 4).

Implements Surface.

Scroll()

virtual bool Scroll ( const IntRect & rect, int dx, int dy )

overridevirtual

Shift a rectangle of pixels by an offset.

The library calls this during Renderer::Render() when a page scrolls, moving already painted pixels instead of repainting them. Afterward, the library repaints only the exposed strip.

The Surface pixel buffer is the source the library paints into. The destination is wherever you copy those pixels to display them (eg, a GPU texture or a window). Scroll() always shifts the source.

Most implementations do this with one call to ShiftPixels().

Parameters

rect	The rectangle to shift (in pixels). This always lies inside the surface, and the shift is smaller than the rectangle on each axis.
dx	The horizontal shift, in pixels (positive moves pixels to the right).
dy	The vertical shift, in pixels (positive moves pixels down).

Returns

Return false in most cases. This means the destination was not shifted. The library then adds rect to dirty_bounds() so you copy the moved pixels from the source to the destination again. Return true only in the rare case where you shifted the destination by the same offset yourself (eg, you scrolled your window or copied within your GPU texture)– the library then reports only the newly exposed strip as dirty.

Note

This is called while pixels are locked (between LockPixels() and UnlockPixels()). Shift through the pointer you returned from LockPixels()– do not lock the buffer again.

Note

Rows may be padded. Step rows by row_bytes(), never by width * 4.

Implements Surface.

size()

virtual size_t size ( ) const

overridevirtual

Size in bytes.

Implements Surface.

UnlockPixels()

virtual void UnlockPixels ( )

overridevirtual

Unlock the pixel buffer.

Implements Surface.

width()

virtual uint32_t width ( ) const

overridevirtual

Width (in pixels).

Implements Surface.

Friends And Related Symbol Documentation

BitmapSurfaceFactory

friend class BitmapSurfaceFactory

friend

Member Data Documentation

impl_

void* impl_

protected

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The documentation for this class was generated from the following file:

• Ultralight/platform/Surface.h