# ImageSourceAdapter The `ImageSourceAdapter` class is an abstract class representing an adapter for image sources, providing a framework for fetching, buffering, and managing images from various sources. Implementations must provide specific mechanisms for image retrieval and handling. | Name | Description | | --------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------- | | [addImageToBuffer()](#addimagetobuffer) | Adds an image to the internal buffer. | | [clearBuffer()](#clearbuffer) | Clears all images from the buffer, resetting the state for new image fetching. | | [getBufferOverflowProtectionMode()](#getbufferoverflowprotectionmode) | Returns the current mode for handling buffer overflow situations. | | [getColourChannelUsageType()](#getcolourchannelusagetype) | Retrieves the current usage type for color channels in images. | | [getImage()](#getimage) | Returns a buffered image. | | [getImageCount()](#getimagecount) | Retrieves the current number of images in the buffer. | | [getMaxImageCount()](#getmaximagecount) | Returns the maximum number of images that can be buffered at any time. | | [hasImage()](#hasimage) | Checks if an image with the specified ID is present in the buffer. | | [hasNextImageToFetch()](#hasnextimagetofetch) | Determines whether there are more images available to fetch. | | [isBufferEmpty()](#isbufferempty) | Determines whether the buffer is currently empty. | | [setErrorListener()](#seterrorlistener) | Sets an error listener to receive notifications about errors that occur during image source operations. | | [setBufferOverflowProtectionMode()](#setbufferoverflowprotectionmode) | Sets the behavior for handling new incoming images when the buffer is full. | | [setColourChannelUsageType()](#setcolourchannelusagetype) | Sets the usage type for color channels in images. | | [setMaxImageCount()](#setmaximagecount) | Sets the maximum number of images the buffer can hold. | | [setNextImageToReturn()](#setnextimagetoreturn) | Sets the processing priority of a specific image, affecting the order in which images are returned. | | [startFetching()](#startfetching) | Starts the process of fetching images. | | [stopFetching()](#stopfetching) | Stops the process of fetching images. | ## addImageToBuffer Adds an image to the internal buffer. ```typescript addImageToBuffer(image: DSImageData): void; ``` **Parameters** `image`: The image to add to the buffer. **Return value** None. ## clearBuffer Clears all images from the buffer, resetting the state for new image fetching. ```typescript clearBuffer(): void; ``` **Parameters** None. **Return value** None. ## getBufferOverflowProtectionMode Returns the current mode for handling buffer overflow situations. ```typescript getBufferOverflowProtectionMode(): EnumBufferOverflowProtectionMode; ``` **Parameters** None. **Return value** The current buffer overflow protection mode. **See Also** [EnumBufferOverflowProtectionMode](https://www.dynamsoft.com/capture-vision/docs/core/enums/core/buffer-overflow-protection-mode.md) ## getColourChannelUsageType Retrieves the current usage type for color channels in images. ```typescript getColourChannelUsageType(): EnumColourChannelUsageType; ``` **Parameters** None. **Return value** The current usage type for color channels in images. **See Also** [EnumColourChannelUsageType](https://www.dynamsoft.com/capture-vision/docs/core/enums/core/colour-channel-usage-type.md) ## getImage Returns a buffered image. ```typescript getImage(): Promise; ``` **Parameters** None. **Return value** A promise that resolves with an instance of `DSImageData`. ## getImageCount Retrieves the current number of images in the buffer. ```typescript getImageCount(): number; ``` **Parameters** None. **Return value** The actual count of buffered images. ## getMaxImageCount Returns the maximum number of images that can be buffered at any time. ```typescript getMaxImageCount(): number; ``` **Parameters** None. **Return value** The maximum number of images that can be buffered. ## hasImage Checks if an image with the specified ID is present in the buffer. ```typescript hasImage(imageId: number): boolean; ``` **Parameters** `imageId`: The ID of the image to check. **Return value** True if the image is in the buffer, false otherwise. ## hasNextImageToFetch Determines whether there are more images available to fetch. This is an abstract method that needs to be implemented by the user. ```typescript abstract hasNextImageToFetch(): boolean; ``` **Parameters** None. **Return value** True if there are more images left to fetch, false otherwise. ## isBufferEmpty Determines whether the buffer is currently empty. ```typescript isBufferEmpty(): boolean; ``` **Parameters** None. **Return value** True if the buffer is empty, false otherwise. ## setErrorListener Sets an error listener to receive notifications about errors that occur during image source operations. Implementing classes should invoke the listener's onErrorReceived method with relevant error details when error occur. ```typescript setErrorListener: (listener: ImageSourceErrorListener) => void; ``` **Parameters** `listener`: an instance of `ImageSourceErrorListener` or its derived class to handle error notifications. **Return value** None. **Code Snippet** ```javascript cameraEnhancer.setErrorListener({ onErrorReceived: (errorCode, errorMessage) => { console.log(errorMessage); }, }); ``` **See Also** [ImageSourceErrorListener](https://www.dynamsoft.com/capture-vision/docs/web/programming/javascript/api-reference/core/basic-structures/image-source-error-listener.md) ## setBufferOverflowProtectionMode Sets the behavior for handling new incoming images when the buffer is full. ```typescript setBufferOverflowProtectionMode(mode: EnumBufferOverflowProtectionMode): void; ``` **Parameters** `mode`: One of the modes defined in `EnumBufferOverflowProtectionMode`, specifying how to handle buffer overflow. **Return value** None. **See Also** [EnumBufferOverflowProtectionMode](https://www.dynamsoft.com/capture-vision/docs/core/enums/core/buffer-overflow-protection-mode.md) ## setColourChannelUsageType Sets the usage type for color channels in images. ```typescript setColourChannelUsageType(type: EnumColourChannelUsageType): void; ``` **Parameters** `type`: one of the types defined in `EnumColourChannelUsageType`, specifying how color channels should be used. **Return value** None. **See Also** [EnumColourChannelUsageType](https://www.dynamsoft.com/capture-vision/docs/core/enums/core/colour-channel-usage-type.md) ## setMaxImageCount Sets the maximum number of images the buffer can hold. ```typescript setMaxImageCount(count: number): void; ``` **Parameters** `count`: The maximum number of images that can be buffered. **Return value** None. ## setNextImageToReturn Sets the processing priority of a specific image, affecting the order in which images are returned. ```typescript setNextImageToReturn(imageId: number, keepInBuffer?: boolean): void; ``` **Parameters** `imageId`: The ID of the next image to return. `keepInBuffer`: Optional. Whether the image should be kept in the buffer after it is returned. **Return value** None. ## startFetching Starts the process of fetching images. ```typescript startFetching(): void; ``` **Parameters** None. **Return value** None. ## stopFetching Stops the process of fetching images. ```typescript stopFetching(): void; ``` **Parameters** None. **Return value** None.