Image
Overview
Provides APIs for obtaining pixel map data and information.
@Syscap SystemCapability.Multimedia.Image
Since: 8
Summary
Files
| Name | Description |
|---|---|
| image_pixel_map_napi.h | Declares the APIs that can lock, access, and unlock pixel map data. File to Include: <multimedia/image_framework/image_pixel_map_napi.h> |
Structs
| Name | Description |
|---|---|
| OhosPixelMapInfo | Defines the pixel map information. |
| OhosPixelMapCreateOps | Defines the options used for creating a pixel map. |
Types
| Name | Description |
|---|---|
| NativePixelMap | Defines the data type name of the native pixel map. |
Enums
| Name | Description |
|---|---|
| { OHOS_IMAGE_RESULT_SUCCESS = 0, OHOS_IMAGE_RESULT_BAD_PARAMETER = -1 } | Enumerates the error codes returned by a function. |
| { OHOS_PIXEL_MAP_FORMAT_NONE = 0, OHOS_PIXEL_MAP_FORMAT_RGBA_8888 = 3, OHOS_PIXEL_MAP_FORMAT_RGB_565 = 2 } | Enumerates the pixel formats. |
| { OHOS_PIXEL_MAP_ALPHA_TYPE_UNKNOWN = 0, OHOS_PIXEL_MAP_ALPHA_TYPE_OPAQUE = 1, OHOS_PIXEL_MAP_ALPHA_TYPE_PREMUL = 2, OHOS_PIXEL_MAP_ALPHA_TYPE_UNPREMUL = 3 } | Enumerates the pixel map alpha types. |
| { OHOS_PIXEL_MAP_SCALE_MODE_FIT_TARGET_SIZE = 0, OHOS_PIXEL_MAP_SCALE_MODE_CENTER_CROP = 1 } | Enumerates the pixel map scale modes. |
| { OHOS_PIXEL_MAP_READ_ONLY = 0, OHOS_PIXEL_MAP_EDITABLE = 1 } | Enumerates the pixel map editing types. |
Functions
| Name | Description |
|---|---|
| OH_GetImageInfo (napi_env env, napi_value value, OhosPixelMapInfo *info) | Obtains the PixelMap information and stores the information to the OhosPixelMapInfo structure. |
| OH_AccessPixels (napi_env env, napi_value value, void **addrPtr) | Obtains the memory address of the PixelMap object data and locks the memory. |
| OH_UnAccessPixels (napi_env env, napi_value value) | Unlocks the memory of the PixelMap object data. This function is used with OH_AccessPixels in pairs. |
| OH_PixelMap_CreatePixelMap (napi_env env, OhosPixelMapCreateOps info, void *buf, size_t len, napi_value *res) | Creates a PixelMap object. |
| OH_PixelMap_CreateAlphaPixelMap (napi_env env, napi_value source, napi_value *alpha) | Creates a PixelMap object that contains only alpha channel information. |
| OH_PixelMap_InitNativePixelMap (napi_env env, napi_value source) | Initializes a PixelMap object. |
| OH_PixelMap_GetBytesNumberPerRow (const NativePixelMap *native, int32_t *num) | Obtains the number of bytes per row of a PixelMap object. |
| OH_PixelMap_GetIsEditable (const NativePixelMap *native, int32_t *editable) | Checks whether a PixelMap object is editable. |
| OH_PixelMap_IsSupportAlpha (const NativePixelMap *native, int32_t *alpha) | Checks whether a PixelMap object supports alpha channels. |
| OH_PixelMap_SetAlphaAble (const NativePixelMap *native, int32_t alpha) | Sets an alpha channel for a PixelMap object. |
| OH_PixelMap_GetDensity (const NativePixelMap *native, int32_t *density) | Obtains the pixel density of a PixelMap object. |
| OH_PixelMap_SetDensity (const NativePixelMap *native, int32_t density) | Sets the pixel density for a PixelMap object. |
| OH_PixelMap_SetOpacity (const NativePixelMap *native, float opacity) | Sets the opacity for a PixelMap object. |
| OH_PixelMap_Scale (const NativePixelMap *native, float x, float y) | Scales a PixelMap object. |
| OH_PixelMap_Translate (const NativePixelMap *native, float x, float y) | Translates a PixelMap object. |
| OH_PixelMap_Rotate (const NativePixelMap *native, float angle) | Rotates a PixelMap object. |
| OH_PixelMap_Flip (const NativePixelMap *native, int32_t x, int32_t y) | Flips a PixelMap object. |
| OH_PixelMap_Crop (const NativePixelMap *native, int32_t x, int32_t y, int32_t width, int32_t height) | Crops a PixelMap object. |
Type Description
NativePixelMap
typedef struct NativePixelMapNativePixelMap
Description:
Defines the data type name of the native pixel map.
Enum Description
anonymous enum
anonymous enum
Description
Enumerates the error codes returned by a function.
| Name | Description |
|---|---|
| OHOS_IMAGE_RESULT_SUCCESS | Operation success. |
| OHOS_IMAGE_RESULT_BAD_PARAMETER | Invalid value. |
anonymous enum
anonymous enum
Description
Enumerates the pixel formats.
| Name | Description |
|---|---|
| OHOS_PIXEL_MAP_FORMAT_NONE | Unknown format. |
| OHOS_PIXEL_MAP_FORMAT_RGBA_8888 | 32-bit RGBA, with 8 bits each for R (red), G (green), B (blue), and A (alpha). The data is stored from the most significant bit to the least significant bit. |
| OHOS_PIXEL_MAP_FORMAT_RGB_565 | 16-bit RGB, with 5, 6, and 5 bits for R, G, and B, respectively. The storage sequence is from the most significant bit to the least significant bit. |
anonymous enum
anonymous enum
Description:
Enumerates the pixel map alpha types.
| Name | Description |
|---|---|
| OHOS_PIXEL_MAP_ALPHA_TYPE_UNKNOWN | Unknown format. |
| OHOS_PIXEL_MAP_ALPHA_TYPE_OPAQUE | Opaque format. |
| OHOS_PIXEL_MAP_ALPHA_TYPE_PREMUL | Premultiplied format. |
| OHOS_PIXEL_MAP_ALPHA_TYPE_UNPREMUL | Unpremultiplied format. |
anonymous enum
anonymous enum
Description:
Enumerates the pixel map scale modes.
| Name | Description |
|---|---|
| OHOS_PIXEL_MAP_SCALE_MODE_FIT_TARGET_SIZE | Adaptation to the target image size. |
| OHOS_PIXEL_MAP_SCALE_MODE_CENTER_CROP | Cropping the center portion of an image to the target size. |
anonymous enum
anonymous enum
Description:
Enumerates the pixel map editing types.
| Name | Description |
|---|---|
| OHOS_PIXEL_MAP_READ_ONLY | Read-only. |
| OHOS_PIXEL_MAP_EDITABLE | Editable. |
Function Description
OH_AccessPixels()
int32_t OH_AccessPixels (napi_env env, napi_value value, void ** addrPtr )
Description
Obtains the memory address of the PixelMap object data and locks the memory.
After the function is executed successfully, *addrPtr is the address of the memory to be accessed. After the access operation is complete, you must use OH_UnAccessPixels to unlock the memory. Otherwise, the resources in the memory cannot be released. After being unlocked, the memory address cannot be accessed or operated.
Parameters
| Name | Description |
|---|---|
| env | Indicates the NAPI environment pointer. |
| value | Indicates the PixelMap object at the application layer. |
| addrPtr | Indicates the double pointer to the memory address. |
See
UnAccessPixels
Returns
Returns OHOS_IMAGE_RESULT_SUCCESS if the operation is successful; returns an error code otherwise.
OH_GetImageInfo()
int32_t OH_GetImageInfo (napi_env env, napi_value value, OhosPixelMapInfo * info )
Description
Obtains the PixelMap information and stores the information to the OhosPixelMapInfo structure.
Parameters
| Name | Description |
|---|---|
| env | Indicates the NAPI environment pointer. |
| value | Indicates the PixelMap object at the application layer. |
| info | Indicates the pointer to the object that stores the information obtained. For details, see OhosPixelMapInfo. |
Returns
Returns 0 if the information is obtained and stored successfully; returns an error code otherwise.
See
OH_UnAccessPixels()
int32_t OH_UnAccessPixels (napi_env env, napi_value value )
Description
Unlocks the memory of the PixelMap object data. This function is used with OH_AccessPixels in pairs.
Parameters
| Name | Description |
|---|---|
| env | Indicates the NAPI environment pointer. |
| value | Indicates the PixelMap object at the application layer. |
Returns
Returns OHOS_IMAGE_RESULT_SUCCESS if the operation is successful; returns an error code otherwise.
See
AccessPixels
OH_PixelMap_CreateAlphaPixelMap()
int32_t OH_PixelMap_CreateAlphaPixelMap (napi_env env, napi_value source, napi_value * alpha )
Description:
Creates a PixelMap object that contains only alpha channel information.
Parameters
| Name | Description |
|---|---|
| env | Indicates the NAPI environment pointer. |
| source | Indicates the options for setting the PixelMap object. |
| alpha | Indicates the pointer to the alpha channel. |
Returns
Returns a PixelMap object if the operation is successful; returns an error code otherwise.
See
CreateAlphaPixelMap
OH_PixelMap_CreatePixelMap()
int32_t OH_PixelMap_CreatePixelMap (napi_env env, OhosPixelMapCreateOps info, void * buf, size_t len, napi_value * res )
Description:
Creates a PixelMap object.
Parameters
| Name | Description |
|---|---|
| env | Indicates the NAPI environment pointer. |
| info | Indicates the options for setting the PixelMap object. |
| buf | Indicates the pointer to the buffer of the image. |
| len | Indicates the image size. |
| res | Indicates the pointer to the PixelMap object at the application layer. |
Returns
Returns a PixelMap object if the operation is successful; returns an error code otherwise.
See
CreatePixelMap
OH_PixelMap_Crop()
int32_t OH_PixelMap_Crop (const NativePixelMap * native, int32_t x, int32_t y, int32_t width, int32_t height )
Description:
Crops a PixelMap object.
Parameters
| Name | Description |
|---|---|
| native | Indicates the pointer to a NativePixelMap object. |
| x | Indicates the x-coordinate of the upper left corner of the target image. |
| y | Indicates the y-coordinate of the upper left corner of the target image. |
| width | Indicates the width of the cropped region. |
| height | Indicates the height of the cropped region. |
Returns
Returns 0 if the operation is successful; returns an error code otherwise.
See
Crop
OH_PixelMap_Flip()
int32_t OH_PixelMap_Flip (const NativePixelMap * native, int32_t x, int32_t y )
Description:
Flips a PixelMap object.
Parameters
| Name | Description |
|---|---|
| native | Indicates the pointer to a NativePixelMap object. |
| x | Specifies whether to flip around the x axis. |
| y | Specifies whether to flip around the y axis. |
Returns
Returns 0 if the operation is successful; returns an error code otherwise.
See
Flip
OH_PixelMap_GetBytesNumberPerRow()
int32_t OH_PixelMap_GetBytesNumberPerRow (const NativePixelMap * native, int32_t * num )
Description:
Obtains the number of bytes per row of a PixelMap object.
Parameters
| Name | Description |
|---|---|
| native | Indicates the pointer to a NativePixelMap object. |
| num | Indicates the pointer to the number of bytes per row of the PixelMap object. |
Returns
Returns the number of bytes per row of the PixelMap object if the operation is successful; returns an error code otherwise.
See
GetBytesNumberPerRow
OH_PixelMap_GetDensity()
int32_t OH_PixelMap_GetDensity (const NativePixelMap * native, int32_t * density )
Description:
Obtains the pixel density of a PixelMap object.
Parameters
| Name | Description |
|---|---|
| native | Indicates the pointer to a NativePixelMap object. |
| density | Indicates the pointer to the pixel density. |
Returns
Returns the pixel density if the operation is successful; returns an error code otherwise.
See
GetDensity
OH_PixelMap_GetImageInfo()
int32_t OH_PixelMap_GetImageInfo (const NativePixelMap * native, OhosPixelMapInfo * info )
Description:
Obtains the image information of a PixelMap object.
Parameters
| Name | Description |
|---|---|
| native | Indicates the pointer to a NativePixelMap object. |
| info | Indicates the pointer to the image information. |
Returns
Returns 0 if the operation is successful; returns an error code otherwise.
See
OH_PixelMap_GetIsEditable()
int32_t OH_PixelMap_GetIsEditable (const NativePixelMap * native, int32_t * editable )
Description:
Checks whether a PixelMap object is editable.
Parameters
| Name | Description |
|---|---|
| native | Indicates the pointer to a NativePixelMap object. |
| editable | Indicates the pointer to the editing type of the PixelMap object. |
Returns
Returns an enumerated value that indicates the editing type of the PixelMap object if the operation is successful; returns an error code otherwise.
See
GetIsEditable
OH_PixelMap_InitNativePixelMap()
NativePixelMap* OH_PixelMap_InitNativePixelMap (napi_env env, napi_value source )
Description:
Initializes a PixelMap object.
Parameters
| Name | Description |
|---|---|
| env | Indicates the NAPI environment pointer. |
| source | Indicates the options for setting the PixelMap object. |
Returns
Returns a pointer to the NativePixelMap object if the operation is successful; returns an error code otherwise.
See
InitNativePixelMap
OH_PixelMap_IsSupportAlpha()
int32_t OH_PixelMap_IsSupportAlpha (const NativePixelMap * native, int32_t * alpha )
Description:
Checks whether a PixelMap object supports alpha channels.
Parameters
| Name | Description |
|---|---|
| native | Indicates the pointer to a NativePixelMap object. |
| alpha | Indicates the pointer to the support for alpha channels. |
Returns
Returns 0 if the operation is successful; returns an error code otherwise.
See
IsSupportAlpha
OH_PixelMap_Rotate()
int32_t OH_PixelMap_Rotate (const NativePixelMap * native, float angle )
Description:
Rotates a PixelMap object.
Parameters
| Name | Description |
|---|---|
| native | Indicates the pointer to a NativePixelMap object. |
| angle | Indicates the angle to rotate. |
Returns
Returns 0 if the operation is successful; returns an error code otherwise.
See
Rotate
OH_PixelMap_Scale()
int32_t OH_PixelMap_Scale (const NativePixelMap * native, float x, float y )
Description:
Scales a PixelMap object.
Parameters
| Name | Description |
|---|---|
| native | Indicates the pointer to a NativePixelMap object. |
| x | Indicates the scaling ratio of the width. |
| y | Indicates the scaling ratio of the height. |
Returns
Returns 0 if the operation is successful; returns an error code otherwise.
See
Scale
OH_PixelMap_SetAlphaAble()
int32_t OH_PixelMap_SetAlphaAble (const NativePixelMap * native, int32_t alpha )
Description:
Sets an alpha channel for a PixelMap object.
Parameters
| Name | Description |
|---|---|
| native | Indicates the pointer to a NativePixelMap object. |
| alpha | Indicates the alpha channel to set. |
Returns
Returns 0 if the operation is successful; returns an error code otherwise.
See
SetAlphaAble
OH_PixelMap_SetDensity()
int32_t OH_PixelMap_SetDensity (const NativePixelMap * native, int32_t density )
Description:
Sets the pixel density for a PixelMap object.
Parameters
| Name | Description |
|---|---|
| native | Indicates the pointer to a NativePixelMap object. |
| density | Indicates the pixel density to set. |
Returns
Returns 0 if the operation is successful; returns an error code otherwise.
See
GetDensity
OH_PixelMap_SetOpacity()
int32_t OH_PixelMap_SetOpacity (const NativePixelMap * native, float opacity )
Description:
Sets the opacity for a PixelMap object.
Parameters
| Name | Description |
|---|---|
| native | Indicates the pointer to a NativePixelMap object. |
| opacity | Indicates the opacity to set. |
Returns
Returns 0 if the operation is successful; returns an error code otherwise.
See
SetOpacity
OH_PixelMap_Translate()
int32_t OH_PixelMap_Translate (const NativePixelMap * native, float x, float y )
Description:
Translates a PixelMap object.
Parameters
| Name | Description |
|---|---|
| native | Indicates the pointer to a NativePixelMap object. |
| x | Indicates the horizontal distance to translate. |
| y | Indicates the vertical distance to translate. |
Returns
Returns 0 if the operation is successful; returns an error code otherwise.
See
Translate
OH_PixelMap_UnAccessPixels()
int32_t OH_PixelMap_UnAccessPixels (const NativePixelMap * native)
Description:
Unlocks the memory of the NativePixelMap object data. This function is used with OH_PixelMap_AccessPixels in pairs.
Parameters
| Name | Description |
|---|---|
| native | Indicates the pointer to a NativePixelMap object. |
Returns
Returns OHOS_IMAGE_RESULT_SUCCESS if the operation is successful; returns an error code otherwise.
See
AccessPixels
OH_PixelMap_AccessPixels()
int32_t OH_PixelMap_AccessPixels(const NativePixelMap* native, void** addr)
Description:
Obtains the memory address of a NativePixelMap object and locks the memory.
Parameters
| Name | Description |
|---|---|
| native | Indicates the pointer to a NativePixelMap object. |
| addr | Indicates the double pointer to the memory address. |
Returns
Returns OHOS_IMAGE_RESULT_SUCCESS if the operation is successful; returns an error code otherwise.
See
UnAccessPixels
OH_UnAccessPixels()
int32_t OH_UnAccessPixels (napi_env env, napi_value value )
Description:
Unlocks the memory of a PixelMap object. This function is used with OH_AccessPixels in pairs.
Parameters
| Name | Description |
|---|---|
| env | Indicates the NAPI environment pointer. |
| value | Indicates the PixelMap object at the application layer. |
Returns
Returns OHOS_IMAGE_RESULT_SUCCESS if the operation is successful; returns an error code otherwise.
See
AccessPixels