具体的API翻译见http://www.cnblogs.com/over140/archive/2011/11/21/2256727.html
Bitmap
extends Object
implements Parcelable
java.lang.Object | |
↳ | android.graphics.Bitmap |
内部类
详细说明位图的压缩格式,支持JPEG
,PNG ,WEBP
enum Bitmap.Config
位图的结构,ALPHA_8 ,ARGB_4444,ARGB_8888
,RGB_565
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int quality, OutputStream stream) Write a compressed version of the bitmap to the specified outputstream.
把位图的压缩信息写入到一个指定的输出流中。如果返回true,可以通过传递一个相应的输出流到BitmapFactory.decodeStream()来重构该位图。 注意:并非所有的格式都直接支持位图结构,所以通过BitmapFactory返回的位图很可能有不同的位深度,或许会丢失每个象素的alpha值 (例如,JPEG 只支持不透明像素)。 (译者注:色深(color depth),也称色位深度(bitdePth),是指在一定分辨率下一个像素能够接受的颜色数量范围。通常,色深用2的n次方来表示。 例如,8 bit的色深包含2的8次方) 参数 format 图像的压缩格式; quality 图像压缩比的值,0-100。 0 意味着小尺寸压缩,100意味着高质量压缩。对于有些格式,比如无损压缩的PNG, 它就会忽视quality这个参数设置。 stream 写入压缩数据的输出流 返回值 如果成功地把压缩数据写入输出流,则返回true 该方法可以实现Bitmap保存为图片,图片格式为压缩格式 |
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boolean isMutable) Tries to make a new bitmap based on the dimensions of this bitmap, setting the new bitmap's config to the one specified, and then copying
this bitmap's pixels into the new bitmap.
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Copy the pixels from the buffer, beginning at the current position, overwriting the bitmap's pixels.
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Copy the bitmap's pixels into the specified buffer (allocated by the caller).
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int x, int y, int width, int height, Matrix m, boolean filter) Returns an immutable bitmap from subset of the source bitmap, transformed by the optional matrix.
从原始位图剪切图像,并根据可选的矩阵进行转换。它被初始化为跟源位图有同样的密度
该方法是最终的实现,下面的几个方法都是该方法的封装。
参数说明:
Bitmap source:要从中截图的原始位图 int x:起始x坐标 int y:起始y坐标 int width:要截的图的宽度 int height:要截的图的宽度 Matrix(矩阵)来实现旋转等高级方式截图
filter 如果为true,源图要被过滤。该参数仅在matrix包含了超过一个翻转才有效
返回值:返回一个剪切好的Bitmap
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width, int height, Bitmap.Config config) Returns a mutable bitmap with the specified width and height.
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int x, int y, int width, int height) Returns an immutable bitmap from the specified subset of the source bitmap.
从源Bitmap中指定区域(x,y,
width, height)中挖出一块来实现剪切 |
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colors, int offset, int stride, int width, int height, Bitmap.Config config) Returns a immutable bitmap with the specified width and height, with each pixel value set to the corresponding value in the colors array.
返回一个指定宽度和高度的不可变位图,该位图每个像素值等于颜色数组中对应的值。它初始化的密度由getDensity()来设定。 参数 colors 用来初始化像素值得颜色数组 offset 在像素数组的第一个颜色值之前要忽略的像素个数 stride 行之间像素个数 width 位图的宽度 height 位图的高度 config 位图的结构。如果这个结构不支持每个像素的alpha通道(比如,RGB_565), 那么colors数组中的alpha位将被忽略 (被假定为FF值)。 异常 IllegalArgumentException 如果宽度值或高度值小于等于零,或者像素数组的长度小于像素个数,该异常被抛出。 |
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Returns an immutable bitmap from the source bitmap.
从原位图src复制出一个新的位图,和原始位图相同
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colors, int width, int height, Bitmap.Config config) Returns a immutable bitmap with the specified width and height, with each pixel value set to the corresponding value in the colors array.
这个函数根据颜色数组来创建位图,注意:颜色数组的长度>=width*height
此函数创建位图的过程可以简单概括为:以width和height创建空位图,然后用指定的颜色数组colors来从左到右从上至下一次填充颜色。
config是一个枚举,可以用它来指定位图“质量”。
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int dstWidth, int dstHeight, boolean filter) Creates a new bitmap, scaled from an existing bitmap.
把源Bitmap缩放为宽和高(dstWidth
dstHeight)的Bitmap |
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No special parcel contents.
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c) Fills the bitmap's pixels with the specified
Color . |
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Returns a new bitmap that captures the alpha values of the original.
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int[] offsetXY) Returns a new bitmap that captures the alpha values of the original.
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Returns the number of bytes used to store this bitmap's pixels.
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If the bitmap's internal config is in one of the public formats, return that config, otherwise return null.
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Returns the density for this bitmap. |
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Returns the generation ID of this bitmap.
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Returns the bitmap's height
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Returns an optional array of private data, used by the UI system for some bitmaps.
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x, int y) Returns the
Color atthe specified location. |
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pixels, int offset, int stride, int x, int y, int width, int height) Returns in pixels[] a copy of the data in the bitmap.
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Return the number of bytes between rows in the bitmap's pixels.
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targetDensity) Convenience method that returns the height of this bitmap divided by the density scale factor.
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targetDensity) Convenience method that returns the width of this bitmap divided by the density scale factor.
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Returns the bitmap's width
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Returns true if the bitmap's config supports per-pixel alpha, and if the pixels may contain non-opaque alpha values.
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Returns true if the bitmap is marked as mutable (i.e.
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Returns true if this bitmap has been recycled.
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Rebuilds any caches associated with the bitmap that are used for drawing it.
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Free the native object associated with this bitmap, and clear the reference to the pixel data.
释放和位图相关的本地对象,且清除对像素数据的引用。该方法不会同步释放像素数据。它仅仅允许在没有其它引用的情况
下被系统垃圾回收。这个位图被标记为“死的”,意味着如果getPixels()或setPixels()被调用,一个异常会抛出,
且它不画任何东西。这个操作不可翻转,所以只有当你确信这个位图没有更多的用处时,它才能被调用。这是一个
高级的调用, 且一般来说它不需要被调用,因为通常的垃圾回收过程会在该位图没有其它引用的时候,释放这些内存。
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Given another bitmap, return true if it has the same dimensions, config, and pixel data as this bitmap.
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density) Specifies the density for this bitmap. |
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hasAlpha) Tell the bitmap if all of the pixels are known to be opaque (false) or if some of the pixels may contain non-opaque alpha values (true).
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x, int y, int color) Write the specified
Color intothe bitmap (assuming it is mutable) at the x,y coordinate. |
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pixels, int offset, int stride, int x, int y, int width, int height) Replace pixels in the bitmap with the colors in the array.
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int flags) Write the bitmap and its pixels to the parcel.
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