android处理图片的一些问题总结

1

java.lang.OutOfMemoryError:
bitmap size exceedsVM budget

01

Bitmap
bitmap =

null

;

02

if

(mUseZoomOut
|| mUseZoomIn) {

03

//
decode image size (decode metadata only, not the whole image)

04

o
=

new

BitmapFactory.Options();

05

o.inJustDecodeBounds
=

true

;

06

stream
=

new

FileInputStream(filename);

07

BitmapFactory.decodeStream(stream,

null

,
o);

08

stream.close();

09

10

//
get original image size

11

int

inWidth
=  o.outWidth;

12

int

inHeight
= o.outHeight;

13

clog(String.format(

"Original
bitmap size: (%dx%d)."

,
inWidth, inHeight));

14

15

//
get size for pre-resized image

16

o
=

new

Options();

17

o.inSampleSize
= Math.max(inWidth/targetWidth, inHeight/targetHeight);

18

}

19

20

//
decode pre-resized image

21

stream
=

new

FileInputStream(filename);

22

//
o.inPurgeable = true;

23

bitmap
= BitmapFactory.decodeStream(stream,

null

,
o);

24

stream.close();

25

clog(String.format(

"Pre-sized
bitmap size: (%dx%d)."

,
bitmap.getWidth(), bitmap.getHeight()));

1

android:largeHeap=

"true"

1

Whether
your application

's
processesshould be created with a large Dalvik heap. Thisappliesto all processescreated for the application. It only appliesto the first application loaded into a process; if you'

re
using a shared user ID to allow multiple applicationsto use a process, they all must use

this

option
consistently or they will have unpredictable results.

2

Most
appsshould not need

this

and
should instead focuson reducing their overall memory usage

for

improved
performance. Enabling

this

also
doesnot guarantee a fixed increase in available memory, because some devicesare constrained by their total available memory.

3

To
query the available memory size at runtime, use the methodsgetMemoryClass() or getLargeMemoryClass().

1

Bitmap
too large to be uploaded into a texture exception

1

android:hardwareAccelerated=

"false"

2

3

android:hardwareAccelerated

4

Whether
or not hardware-accelerated rendering should be enabled

for

all
activitiesand viewsin

this

application
—

"true"

if

it
should be enabled, and

"false"

if

not.
The

default

value
is

"true"

if

you

've
set either minSdkVersion or targetSdkVersion to "14" or higher; otherwise, it'

s

"false"

.

5

Starting
from Android

3.0

(API
level

11

),
a hardware-accelerated OpenGL renderer isavailable to applications, to improve performance 

for

many
common 2D graphicsoperations. When the hardware-accelerated renderer isenabled, most operationsin Canvas, Paint, Xfermode, ColorFilter, Shader, and Camera are accelerated. Thisresultsin smoother animations, smoother scrolling, and improved responsiveness
overall, even 

for

applications
that

do

not
explicitly make use the framework'sOpenGL libraries.

6

Note
that not all of the OpenGL 2D operationsare accelerated. If you enable the hardware-accelerated renderer, test your application to ensure that it can make use of the renderer without errors.

7

For
more information, read the Hardware Acceleration guide.

1

public

void

drawBitmap
(Bitmap bitmap, Rect src, RectF dst, Paint paint)

2

3

public

Bitmap
decodeRegion (Rect rect, BitmapFactory.Optionsoptions)