BitmapFactory.Options
public
static
class
BitmapFactory.Options
extends Object
java.lang.Object | |
↳ | android.graphics.BitmapFactory.Options |
Summary
Fields | |
---|---|
public
Bitmap |
inBitmap
If set, decode methods that take the Options object will attempt to reuse this bitmap when loading content. |
public
int |
inDensity
The pixel density to use for the bitmap. |
public
boolean |
inDither
This field was deprecated
in API level 24.
As of |
public
boolean |
inInputShareable
This field was deprecated
in API level 21.
As of |
public
boolean |
inJustDecodeBounds
If set to true, the decoder will return null (no bitmap), but
the |
public
boolean |
inMutable
If set, decode methods will always return a mutable Bitmap instead of an immutable one. |
public
boolean |
inPreferQualityOverSpeed
This field was deprecated
in API level 24.
As of |
public
ColorSpace |
inPreferredColorSpace
If this is non-null, the decoder will try to decode into this color space. |
public
Bitmap.Config |
inPreferredConfig
If this is non-null, the decoder will try to decode into this internal configuration. |
public
boolean |
inPremultiplied
If true (which is the default), the resulting bitmap will have its color channels pre-multiplied by the alpha channel. |
public
boolean |
inPurgeable
This field was deprecated
in API level 21.
As of For the re-decode to happen, the bitmap must have access to the
encoded data, either by sharing a reference to the input
or by making a copy of it. This distinction is controlled by
inInputShareable. If this is true, then the bitmap may keep a shallow
reference to the input. If this is false, then the bitmap will
explicitly make a copy of the input data, and keep that. Even if
sharing is allowed, the implementation may still decide to make a
deep copy of the input data. While inPurgeable can help avoid big Dalvik heap allocations (from
API level 11 onward), it sacrifices performance predictability since any
image that the view system tries to draw may incur a decode delay which
can lead to dropped frames. Therefore, most apps should avoid using
inPurgeable to allow for a fast and fluid UI. To minimize Dalvik heap
allocations use the Note: This flag is ignored when used
with |
public
int |
inSampleSize
If set to a value > 1, requests the decoder to subsample the original image, returning a smaller image to save memory. |
public
boolean |
inScaled
When this flag is set, if |
public
int |
inScreenDensity
The pixel density of the actual screen that is being used. |
public
int |
inTargetDensity
The pixel density of the destination this bitmap will be drawn to. |
public
byte[] |
inTempStorage
Temp storage to use for decoding. |
public
boolean |
mCancel
This field was deprecated
in API level 24.
As of |
public
ColorSpace |
outColorSpace
If known, the color space the decoded bitmap will have. |
public
Bitmap.Config |
outConfig
If known, the config the decoded bitmap will have. |
public
int |
outHeight
The resulting height of the bitmap. |
public
String |
outMimeType
If known, this string is set to the mimetype of the decoded image. |
public
int |
outWidth
The resulting width of the bitmap. |
Public constructors | |
---|---|
Options()
Create a default Options object, which if left unchanged will give the same result from the decoder as if null were passed. |
Public methods | |
---|---|
void
|
requestCancelDecode()
This method was deprecated
in API level 24.
As of |
Inherited methods | |
---|---|
Fields
inBitmap
public Bitmap inBitmap
If set, decode methods that take the Options object will attempt to
reuse this bitmap when loading content. If the decode operation
cannot use this bitmap, the decode method will throw an
IllegalArgumentException
. The
current implementation necessitates that the reused bitmap be
mutable, and the resulting reused bitmap will continue to remain
mutable even when decoding a resource which would normally result in
an immutable bitmap.
You should still always use the returned Bitmap of the decode method and not assume that reusing the bitmap worked, due to the constraints outlined above and failure situations that can occur. Checking whether the return value matches the value of the inBitmap set in the Options structure will indicate if the bitmap was reused, but in all cases you should use the Bitmap returned by the decoding function to ensure that you are using the bitmap that was used as the decode destination.
Usage with BitmapFactory
As of Build.VERSION_CODES.KITKAT
, any
mutable bitmap can be reused by BitmapFactory
to decode any
other bitmaps as long as the resulting byte count
of the decoded bitmap is less than or equal to the allocated byte count
of the reused
bitmap. This can be because the intrinsic size is smaller, or its
size post scaling (for density / sample size) is smaller.
Prior to Build.VERSION_CODES.KITKAT
additional constraints apply: The image being decoded (whether as a
resource or as a stream) must be in jpeg or png format. Only equal
sized bitmaps are supported, with inSampleSize
set to 1.
Additionally, the configuration
of the reused bitmap will override the setting of
inPreferredConfig
, if set.
Usage with BitmapRegionDecoder
BitmapRegionDecoder will draw its requested content into the Bitmap
provided, clipping if the output content size (post scaling) is larger
than the provided Bitmap. The provided Bitmap's width, height, and
Bitmap.Config
will not be changed.
BitmapRegionDecoder support for inBitmap
was
introduced in Build.VERSION_CODES.JELLY_BEAN
. All
formats supported by BitmapRegionDecoder support Bitmap reuse via
inBitmap
.
inDensity
public int inDensity
The pixel density to use for the bitmap. This will always result
in the returned bitmap having a density set for it (see
Bitmap.setDensity(int)
). In addition,
if inScaled
is set (which it is by default} and this
density does not match inTargetDensity
, then the bitmap
will be scaled to the target density before being returned.
If this is 0,
BitmapFactory#decodeResource(Resources, int)
,
BitmapFactory#decodeResource(Resources, int, android.graphics.BitmapFactory.Options)
,
and BitmapFactory#decodeResourceStream
will fill in the density associated with the resource. The other
functions will leave it as-is and no density will be applied.
inDither
public boolean inDither
This field was deprecated
in API level 24.
As of Build.VERSION_CODES.N
, this is
ignored.
In Build.VERSION_CODES.M
and below, if dither is
true, the decoder will attempt to dither the decoded image.
inInputShareable
public boolean inInputShareable
This field was deprecated
in API level 21.
As of Build.VERSION_CODES.LOLLIPOP
, this is
ignored.
In Build.VERSION_CODES.KITKAT
and below, this
field works in conjunction with inPurgeable. If inPurgeable is false,
then this field is ignored. If inPurgeable is true, then this field
determines whether the bitmap can share a reference to the input
data (inputstream, array, etc.) or if it must make a deep copy.
inJustDecodeBounds
public boolean inJustDecodeBounds
If set to true, the decoder will return null (no bitmap), but
the out...
fields will still be set, allowing the caller to
query the bitmap without having to allocate the memory for its pixels.
inMutable
public boolean inMutable
If set, decode methods will always return a mutable Bitmap instead of an immutable one. This can be used for instance to programmatically apply effects to a Bitmap loaded through BitmapFactory.
Can not be set simultaneously with inPreferredConfig =
Bitmap.Config.HARDWARE
,
because hardware bitmaps are always immutable.
inPreferQualityOverSpeed
public boolean inPreferQualityOverSpeed
This field was deprecated
in API level 24.
As of Build.VERSION_CODES.N
, this is
ignored. The output will always be high quality.
In Build.VERSION_CODES.M
and below, if
inPreferQualityOverSpeed is set to true, the decoder will try to
decode the reconstructed image to a higher quality even at the
expense of the decoding speed. Currently the field only affects JPEG
decode, in the case of which a more accurate, but slightly slower,
IDCT method will be used instead.
inPreferredColorSpace
public ColorSpace inPreferredColorSpace
If this is non-null, the decoder will try to decode into this
color space. If it is null, or the request cannot be met,
the decoder will pick either the color space embedded in the image
or the color space best suited for the requested image configuration
(for instance sRGB
for
Bitmap.Config#ARGB_8888
configuration and
EXTENDED_SRGB
for
Bitmap.Config#RGBA_F16
).
Only ColorSpace.Model#RGB
color spaces are
currently supported. An IllegalArgumentException
will
be thrown by the decode methods when setting a non-RGB color space
such as Lab
.
Prior to Build.VERSION_CODES.UPSIDE_DOWN_CAKE
,
the specified color space's transfer function must be
an ICC parametric curve
. An
IllegalArgumentException
will be thrown by the decode methods
if calling ColorSpace.Rgb#getTransferParameters()
on the
specified color space returns null.
Starting from Build.VERSION_CODES.UPSIDE_DOWN_CAKE
,
non ICC parametric curve transfer function is allowed.
E.g., BT2020_HLG
.
After decode, the bitmap's color space is stored in
outColorSpace
.
inPreferredConfig
public Bitmap.Config inPreferredConfig
If this is non-null, the decoder will try to decode into this
internal configuration. If it is null, or the request cannot be met,
the decoder will try to pick the best matching config based on the
system's screen depth, and characteristics of the original image such
as if it has per-pixel alpha (requiring a config that also does).
Image are loaded with the Bitmap.Config#ARGB_8888
config by
default.
inPremultiplied
public boolean inPremultiplied
If true (which is the default), the resulting bitmap will have its color channels pre-multiplied by the alpha channel.
This should NOT be set to false for images to be directly drawn by
the view system or through a Canvas
. The view system and
Canvas
assume all drawn images are pre-multiplied to simplify
draw-time blending, and will throw a RuntimeException when
un-premultiplied are drawn.
This is likely only useful if you want to manipulate raw encoded image data, e.g. with RenderScript or custom OpenGL.
This does not affect bitmaps without an alpha channel.
Setting this flag to false while setting inScaled
to true
may result in incorrect colors.
inPurgeable
public boolean inPurgeable
This field was deprecated
in API level 21.
As of Build.VERSION_CODES.LOLLIPOP
, this is
ignored.
In Build.VERSION_CODES.KITKAT
and below, if this
is set to true, then the resulting bitmap will allocate its
pixels such that they can be purged if the system needs to reclaim
memory. In that instance, when the pixels need to be accessed again
(e.g. the bitmap is drawn, getPixels() is called), they will be
automatically re-decoded.
For the re-decode to happen, the bitmap must have access to the encoded data, either by sharing a reference to the input or by making a copy of it. This distinction is controlled by inInputShareable. If this is true, then the bitmap may keep a shallow reference to the input. If this is false, then the bitmap will explicitly make a copy of the input data, and keep that. Even if sharing is allowed, the implementation may still decide to make a deep copy of the input data.
While inPurgeable can help avoid big Dalvik heap allocations (from
API level 11 onward), it sacrifices performance predictability since any
image that the view system tries to draw may incur a decode delay which
can lead to dropped frames. Therefore, most apps should avoid using
inPurgeable to allow for a fast and fluid UI. To minimize Dalvik heap
allocations use the inBitmap
flag instead.
Note: This flag is ignored when used
with BitmapFactory.decodeResource(android.content.res.Resources, int, android.graphics.BitmapFactory.Options)
or BitmapFactory.decodeFile(java.lang.String, android.graphics.BitmapFactory.Options)
.
inSampleSize
public int inSampleSize
If set to a value > 1, requests the decoder to subsample the original image, returning a smaller image to save memory. The sample size is the number of pixels in either dimension that correspond to a single pixel in the decoded bitmap. For example, inSampleSize == 4 returns an image that is 1/4 the width/height of the original, and 1/16 the number of pixels. Any value <= 1 is treated the same as 1. Note: the decoder uses a final value based on powers of 2, any other value will be rounded down to the nearest power of 2.
inScaled
public boolean inScaled
When this flag is set, if inDensity
and
inTargetDensity
are not 0, the
bitmap will be scaled to match inTargetDensity
when loaded,
rather than relying on the graphics system scaling it each time it
is drawn to a Canvas.
BitmapRegionDecoder ignores this flag, and will not scale output
based on density. (though inSampleSize
is supported)
This flag is turned on by default and should be turned off if you need a non-scaled version of the bitmap. Nine-patch bitmaps ignore this flag and are always scaled.
If inPremultiplied
is set to false, and the image has alpha,
setting this flag to true may result in incorrect colors.
inScreenDensity
public int inScreenDensity
The pixel density of the actual screen that is being used. This is
purely for applications running in density compatibility code, where
inTargetDensity
is actually the density the application
sees rather than the real screen density.
By setting this, you
allow the loading code to avoid scaling a bitmap that is currently
in the screen density up/down to the compatibility density. Instead,
if inDensity
is the same as inScreenDensity
, the
bitmap will be left as-is. Anything using the resulting bitmap
must also used Bitmap.getScaledWidth
and Bitmap.getScaledHeight
to account for any different between the
bitmap's density and the target's density.
This is never set automatically for the caller by
BitmapFactory
itself. It must be explicitly set, since the
caller must deal with the resulting bitmap in a density-aware way.
inTargetDensity
public int inTargetDensity
The pixel density of the destination this bitmap will be drawn to.
This is used in conjunction with inDensity
and
inScaled
to determine if and how to scale the bitmap before
returning it.
If this is 0,
BitmapFactory#decodeResource(Resources, int)
,
BitmapFactory#decodeResource(Resources, int, android.graphics.BitmapFactory.Options)
,
and BitmapFactory#decodeResourceStream
will fill in the density associated the Resources object's
DisplayMetrics. The other
functions will leave it as-is and no scaling for density will be
performed.
inTempStorage
public byte[] inTempStorage
Temp storage to use for decoding. Suggest 16K or so.
mCancel
public boolean mCancel
This field was deprecated
in API level 24.
As of Build.VERSION_CODES.N
, see
comments on requestCancelDecode()
.
Flag to indicate that cancel has been called on this object. This
is useful if there's an intermediary that wants to first decode the
bounds and then decode the image. In that case the intermediary
can check, inbetween the bounds decode and the image decode, to see
if the operation is canceled.
outColorSpace
public ColorSpace outColorSpace
If known, the color space the decoded bitmap will have. Note that the
output color space is not guaranteed to be the color space the bitmap
is encoded with. If not known (when the config is
Bitmap.Config#ALPHA_8
for instance), or there is an error,
it is set to null.
outConfig
public Bitmap.Config outConfig
If known, the config the decoded bitmap will have. If not known, or there is an error, it is set to null.
outHeight
public int outHeight
The resulting height of the bitmap. If inJustDecodeBounds
is
set to false, this will be height of the output bitmap after any
scaling is applied. If true, it will be the height of the input image
without any accounting for scaling.
outHeight will be set to -1 if there is an error trying to decode.
outMimeType
public String outMimeType
If known, this string is set to the mimetype of the decoded image. If not known, or there is an error, it is set to null.
outWidth
public int outWidth
The resulting width of the bitmap. If inJustDecodeBounds
is
set to false, this will be width of the output bitmap after any
scaling is applied. If true, it will be the width of the input image
without any accounting for scaling.
outWidth will be set to -1 if there is an error trying to decode.
Public constructors
Options
public Options ()
Create a default Options object, which if left unchanged will give the same result from the decoder as if null were passed.
Public methods
requestCancelDecode
public void requestCancelDecode ()
This method was deprecated
in API level 24.
As of Build.VERSION_CODES.N
, this
will not affect the decode, though it will still set mCancel.
In Build.VERSION_CODES.M
and below, if this can
be called from another thread while this options object is inside
a decode... call. Calling this will notify the decoder that it
should cancel its operation. This is not guaranteed to cancel the
decode, but if it does, the decoder... operation will return null,
or if inJustDecodeBounds is true, will set outWidth/outHeight
to -1