Image

Provides APIs for obtaining pixel map data and information.

To use the APIs in this file, libpixelmap_ndk.z.so is required.

@Syscap SystemCapability.Multimedia.Image

Since

Summary

Files

Name	Description
image_pixel_map_napi.h	Declares the APIs that can lock, access, and unlock a pixel map. 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 the functions.
{ 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 struct.
OH_AccessPixels (napi_env env, napi_value value, void **addrPtr)	Obtains the memory address of a PixelMap object and locks the memory.
OH_UnAccessPixels (napi_env env, napi_value value)	Unlocks the memory of a PixelMap object. 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 NativePixelMap

Description

Defines the data type name of the native pixel map.

Since

Enum Description

anonymous enum

anonymous enum

Description

Enumerates the error codes returned by the functions.

Value	Description
OHOS_IMAGE_RESULT_SUCCESS	Operation success.
OHOS_IMAGE_RESULT_BAD_PARAMETER	Invalid value.

Since

anonymous enum

anonymous enum

Description

Enumerates the pixel formats.

Value	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.

Since

anonymous enum

anonymous enum

Description

Enumerates the pixel map alpha types.

Value	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.

Since

anonymous enum

anonymous enum

Description

Enumerates the pixel map scale modes.

Value	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.

Since

anonymous enum

anonymous enum

Description

Enumerates the pixel map editing types.

Value	Description
OHOS_PIXEL_MAP_READ_ONLY	Read-only.
OHOS_PIXEL_MAP_EDITABLE	Editable.

Since

Function Description

OH_AccessPixels()

int32_t OH_AccessPixels (napi_env env, napi_value value, void ** addrPtr )

Description

Obtains the memory address of a PixelMap object 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 the memory is unlocked, its 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.

Since 8

OH_GetImageInfo()

struct OhosPixelMapCreateOps OH_GetImageInfo (napi_env env, napi_value value, OhosPixelMapInfo * info )

Description

Obtains the PixelMap information and stores the information to the OhosPixelMapInfo struct.

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

OhosPixelMapInfo

Since

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

Since

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

Since

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

Since

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

Since

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

Since

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

Since

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

Since

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

Since

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

Since

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

Since

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

Since

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

Since

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

Since

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

Since

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

Since

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

Since