FREBitmapData

newBitmapData

public static FREBitmapData newBitmapData (int width, int height, boolean transparent, Byte[] fillColor)

Creates an FREBitmapData object, which can be returned to the ActionScript side of the extension as a BitmapData instance.

Parameters:

width

The width in pixels. In AIR 3+, there is no arbitrary limit to the width or height of a bitmap (other than the maximum value of an ActionScript signed integer). However, practical memory limits still apply. Bitmap data occupies 32 bits of memory per pixel.

height

The height in pixels.

transparent

Specifies whether this bitmap uses the alpha channel. This parameter corresponds to the hasTransparency() method of the created FREBitmapData and the transparent property of the ActionScript BitmapData object.

fillColor

The 32-bit, ARGB color value with which to fill the new bitmap. If the transparent parameter is false , the alpha component of the color is ignored.

Returns:

FREBitmapData

The FREBitmapData object associated with an ActionScript BitmapData object.

Example:

Byte[] fillColor = {0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf}; 
FREBitmapData bitmap = FREBitmapData.newBitmapData( 320, 200, true, fillColor );

getWidth

public int getWidth()

Returns the width, in pixels, of the bitmap. This value corresponds to the width property of the ActionScript BitmapData class object. You must call this object’s acquire() function before calling this method.

Returns:

int

the number of pixels across the horizontal axis of the bitmap.

getHeight

public int getHeight()

The height, in pixels, of the bitmap. This value corresponds to the height property of the ActionScript BitmapData class object. You must call this object’s acquire() function before calling this method.

Returns:

int

The number of pixels across the vertical axis of the bitmap.

hasAlpha

public boolean hasAlpha()

Indicates whether the bitmap supports per-pixel transparency. This value corresponds to the transparent property of the ActionScript BitmapData class object. If the value is true , then the alpha component of the pixel color values is used. If the value is false , the alpha component of the color is not used. You must call this object’s acquire() function before calling this method.

Returns:

boolean

true if the bitmap uses an alpha channel.

isPremultiplied

public boolean isPremultiplied()

Indicates whether the bitmap pixels are stored as premultiplied color values. A true value means the red, green, and blue components of a pixel color are premultiplied by the alpha component. ActionScript BitmapData objects are currently always premultiplied (but future changes to the runtime could make it possible to create a bitmap that is not premultiplied). For more information about premultiplied color values, see BitmapData.getPixel() in the ActionScript 3.0 Reference for the Adobe Flash Platform . You must call this object’s acquire() function before calling this method.

Returns:

boolean

true if the pixel color components are already multiplied by the alpha component.

getLineStride32

public int getLineStride32()

Specifies the amount of data in each horizontal line of the bitmap. Use this value with the byte array returned by getBits() to parse the image. For example, the position of the pixel immediately below a pixel located at position n in the byte array is n + getLineStride32() . You must call this object’s acquire() function before calling this method.

Returns:

int

The amount of data for each horizontal line in the image.

Example:

The following example moves the position of the byte array containing the pixels colors to the beginning of the third line in a bitmap:

Byte[] fillColor = {0xf,0xf,0xf,0xf,0xf,0xf,0xf,0xf}; 
FREBitmapData bitmap = FREBitmapData.newBitmapData( 320, 200, true, fillColor ); 
int lineStride = bitmap.getLineStride32(); 
bitmap.acquire(); 
ByteBuffer pixels = bitmap.getBits(); 
pixels.position( lineStride * 3 ); 
//do something with the image data 
bitmap.release();

getBits

ByteBuffer getBits()

Returns an array of pixel color values. You must call acquire() before using this method and call release() when you are done modifying the data. If you make changes to the pixel data, call invalidateRect() to notify the AIR runtime that the bitmap has changed. Otherwise, the displayed graphics are not updated.

Returns:

java.nio.ByteBuffer

The image data.

Example:

FREBitmapData bitmap = FREBitmapData.newBitmapData( 320, 200, true, fillColor ); 
bitmap.acquire(); 
ByteBuffer pixels = bitmap.getBits(); 
//do something with the image data 
bitmap.release();

acquire

public void acquire()

Acquires a lock on the image so that the data cannot be modified or disposed by the runtime or application code while you are accessing it. You only need to acquire a lock for bitmaps passed to the function from the ActionScript side of the extension.

While you have a lock, you can only access the data returned by the getBits() function. Accessing or attempting to modify the other properties of the FREBitmapData results in an exception.

invalidateRect

void invalidateRect( int x, int y, int width, int height )

Notifies the runtime that you have changed a region of the image. The screen display of a bitmap data object is not updated unless you call this method. You must call this object’s acquire() function before calling this method.

Parameters:

x

The upper-left corner of the rectangle to invalidate.

y

the upper-left corner of the rectangle to invalidate.

width

the width of the rectangle to invalidate.

height

the height of the rectangle to invalidate.

release

public void release()

Releases the lock obtained by acquire() . You must release the lock before accessing any bitmap properties other than the pixel data returned by getBits() .

isInvertedY

public boolean isInvertedY()

Indicates the order in which the rows of image data are stored. If true , then the last row of image data appears first in the buffer returned by the getBits() method. Images on Android are normally stored starting with the first row of data, so this property is typically false on the Android platform.

Added in AIR 3.1.