net_instaweb::Image Class Reference

Classes
struct	CompressionOptions
struct	ConversionBySourceVariable
struct	ConversionVariables

Public Member Functions
virtual void	Dimensions (ImageDim *natural_dim)=0
size_t	input_size () const
	Returns the size of original input in bytes.
size_t	output_size ()
	Returns the size of output image in bytes.
ImageType	image_type ()
virtual bool	ResizeTo (const ImageDim &new_dim)=0
virtual void	SetTransformToLowRes ()=0
const ContentType *	content_type ()
StringPiece	Contents ()
virtual bool	DrawImage (Image *image, int x, int y)=0
virtual bool	EnsureLoaded (bool output_useful)=0
virtual const GoogleString &	url ()=0
	Returns the image URL.
virtual const GoogleString &	debug_message ()=0
	Returns the debug message.
virtual const GoogleString &	resize_debug_message ()=0
	Returns the resized image debug message.
virtual void	SetDebugMessageUrl (const GoogleString &url)=0
	Sets the URL to be printed in debug messages.

Static Public Member Functions
static const ContentType *	TypeToContentType (ImageType t)
	static method to convert image type to content type.

Protected Member Functions
	Image (const StringPiece &original_contents)
	Image (ImageType type)
virtual void	ComputeImageType ()=0
	Internal helpers.
virtual bool	ComputeOutputContents ()=0
virtual void	SetResizedDimensions (const ImageDim &dim)=0
	Inject desired resized dimensions directly for testing.
virtual bool	ShouldConvertToProgressive (int64 quality) const =0

Protected Attributes
ImageType	image_type_
	Lazily initialized, initially IMAGE_UNKNOWN.
const StringPiece	original_contents_
GoogleString	output_contents_
	Lazily filled.
bool	output_valid_
	Indicates output_contents_ now correct.
bool	rewrite_attempted_
	Indicates if we tried rewriting for this.

Friends
class	ImageTestingPeer
class	ImageTest

Member Function Documentation

const ContentType* net_instaweb::Image::content_type ( )

inline

Returns image-appropriate content type, or NULL if no content type is known. Result is a top-level const pointer and should not be deleted etc.

StringPiece net_instaweb::Image::Contents

(

)

Returns the best known image contents. If image type is not understood, then Contents() will have NULL data().

virtual void net_instaweb::Image::Dimensions ( ImageDim *  natural_dim )

pure virtual

Stores the image dimensions in natural_dim (on success, sets natural_dim->{width, height} and ImageUrlEncoder::HasValidDimensions(natural_dim) == true). This method can fail (ImageUrlEncoder::HasValidDimensions(natural_dim) == false) for various reasons: we don't understand the image format, we can't find the headers, the library doesn't support a particular encoding, etc. In that case the other fields are left alone.

virtual bool net_instaweb::Image::DrawImage ( Image *  image, int  x, int  y  )

pure virtual

Draws the given image on top of this one at the given offset. Returns true if successful.

virtual bool net_instaweb::Image::EnsureLoaded ( bool  output_useful )

pure virtual

Attempts to decode this image and load its raster into memory. If this returns false, future calls to DrawImage and ResizeTo will fail.

If output_useful is true, the decoded version might be written out directly to user, so it may be worthwhile to make it efficient.

virtual bool net_instaweb::Image::ResizeTo ( const ImageDim &  new_dim )

pure virtual

Changes the size of the image to the given width and height. This will run image processing on the image, and return false if the image processing fails. Otherwise the image contents and type can change.

virtual void net_instaweb::Image::SetTransformToLowRes ( )

pure virtual

Enable the transformation to low res image. If low res image is enabled, all jpeg images are transformed to low quality jpeg images and all webp images to low quality webp images, if possible.

virtual bool net_instaweb::Image::ShouldConvertToProgressive ( int64  quality ) const

protectedpure virtual

Determines whether it's a good idea to convert this image to progressive jpeg.

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

• net/instaweb/rewriter/public/image.h