Describes a single image within a Graphics Interchange Format data
stream.
See http://www.w3.org/Graphics/GIF/spec-gif89a.txt section 20.
Declaration Syntax| C# | Visual Basic | Visual C++ |
public class ImageDescriptor : GifComponent
Public Class ImageDescriptor _ Inherits GifComponent
public ref class ImageDescriptor : public GifComponent
Members| All Members | Constructors | Methods | Properties | ||
| Icon | Member | Description |
|---|---|---|
 | ImageDescriptor(Point, Size, Boolean, Boolean, Boolean, Int32) |
Constructor.
|
 | ComponentStatus |
Gets the status of this component, consisting of its error state
and any associated error message.
(Inherited from GifComponent.) |
| ConsolidatedState |
Gets the combined error states of this component and all its child
components.
(Inherited from GifComponent.) |
| Equals(Object) | (Inherited from Object.) |
| ErrorMessage |
Gets any error message associated with the component's error state.
(Inherited from GifComponent.) |
| ErrorState |
Gets the member of the Gif.Components.ErrorState enumeration held
within the ComponentStatus property.
(Inherited from GifComponent.) |
 | Finalize()()() | Allows an Object to attempt to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.) |
 | FromStream(Stream) |
Reads and returns an image descriptor from the supplied stream.
|
| GetHashCode()()() | Serves as a hash function for a particular type. GetHashCode()()() is suitable for use in hashing algorithms and data structures like a hash table. (Inherited from Object.) |
| GetType()()() | Gets the Type of the current instance. (Inherited from Object.) |
| HasLocalColourTable |
Gets a boolean value indicating the presence of a Local Color Table
immediately following this Image Descriptor.
|
| IsInterlaced |
Gets a boolean value indicating whether the image is interlaced. An
image is interlaced in a four-pass interlace pattern; see Appendix E
for details.
|
| IsSorted |
Gets a boolean value indicating whether the Local Color Table is
sorted. If the flag is set, the Local Color Table is sorted, in
order of decreasing importance. Typically, the order would be
decreasing frequency, with most frequent color first. This assists
a decoder, with fewer available colors, in choosing the best subset
of colors; the decoder may use an initial segment of the table to
render the graphic.
|
| LocalColourTableSize |
Gets the actual size of the local colour table.
|
| LocalColourTableSizeBits |
If the Local Color Table Flag is set to 1, the value in this field
is used to calculate the number of bytes contained in the Local
Color Table. To determine that actual size of the color table,
raise 2 to the value of the field + 1.
This value should be 0 if there is no Local Color Table specified.
|
| MemberwiseClone()()() | Creates a shallow copy of the current Object. (Inherited from Object.) |
| Position |
Gets the position, in pixels, of the top-left corner of the image,
with respect to the top-left corner of the logical screen.
Top-left corner of the logical screen is 0,0.
|
| SetStatus(ErrorState, String) |
Sets the ComponentStatus property of thie GifComponent.
(Inherited from GifComponent.) |
| Size |
Gets the size of the image in pixels.
|
| TestState(ErrorState) |
Tests whether the error state of this component or any of its member
components contains the supplied member of the ErrorState
enumeration.
(Inherited from GifComponent.) |
| ToString()()() |
Gets a string representation of the error status of this component
and its subcomponents.
(Inherited from GifComponent.) |
| WriteToStream(Stream) |
Writes this component to the supplied output stream.
(Overrides GifComponent.WriteToStream(Stream).) |
Remarks
Each image in the Data Stream is composed of an Image Descriptor, an
optional Local Color Table, and the image data. Each image must fit
within the boundaries of the Logical Screen, as defined in the
Logical Screen Descriptor.
The Image Descriptor contains the parameters necessary to process a
table based image. The coordinates given in this block refer to
coordinates within the Logical Screen, and are given in pixels. This
block is a Graphic-Rendering Block, optionally preceded by one or more
Control blocks such as the Graphic Control Extension, and may be
optionally followed by a Local Color Table; the Image Descriptor is
always followed by the image data.
This block is REQUIRED for an image. Exactly one Image Descriptor must
be present per image in the Data Stream. An unlimited number of images
may be present per Data Stream.
The scope of this block is the Table-based Image Data Block that
follows it. This block may be modified by the Graphic Control Extension.
Inheritance Hierarchy| Object | ||
 | GifComponent | |
| ImageDescriptor | |