安卓：调整一个大的位图文件缩放输出文件 [英] Android: Resize a large bitmap file to scaled output file

问题描述

我有一个大的位图（例如3888x2592）在一个文件中。现在，我要调整位图到800x533，并将其保存到另一个文件。 我通常会缩放位图通过调用 Bitmap.createBitmap 方法，但它需要一个源位图作为第一个参数，这是我无法提供，因为加载原始图像成位图当然，对象将超出内存（请参阅这里，例如）。

I have a large bitmap (say 3888x2592) in a file. Now, I want to resize that bitmap to 800x533 and save it to another file. I normally would scale the bitmap by calling Bitmap.createBitmap method but it needs a source bitmap as the first argument, which I can't provide because loading the original image into a Bitmap object would of course exceed the memory (see here, for example).

我也无法读取位图，例如， BitmapFactory.de codeFILE（文件，选项），提供 BitmapFactory.Options.inSampleSize ，因为我想将它调整到一个确切的宽度和高度。使用 inSampleSize 将调整位图到972x648（如果我使用 inSampleSize = 4 ）或778x518（如果我使用 inSampleSize = 5 ，这是不是2连电源）。

I also can't read the bitmap with, for example, BitmapFactory.decodeFile(file, options), providing a BitmapFactory.Options.inSampleSize, because I want to resize it to an exact width and height. Using inSampleSize would resize the bitmap to 972x648 (if I use inSampleSize=4) or to 778x518 (if I use inSampleSize=5, which isn't even a power of 2).

我也想避免读取使用inSampleSize与图像，例如，972x648在第一步骤中，然后在第二步骤中它调整到恰好800x533，因为相对于原来的直接调整大小的质量会很差图像。

I would also like to avoid reading the image using inSampleSize with, for example, 972x648 in a first step and then resizing it to exactly 800x533 in a second step, because the quality would be poor compared to a direct resizing of the original image.

要总结一下我的问题： 有没有一种方法来读取与1000万像素以上的大型图像文件并将其保存到一个新的图像文件，调整到一个特定的新高度和宽度，没有得到一个内存不足的异常？

To sum up my question: Is there a way to read a large image file with 10MP or more and save it to a new image file, resized to a specific new width and height, without getting an OutOfMemory exception?

我也试过 BitmapFactory.de codeFILE（文件，选项）并设置Options.outHeight和Options.outWidth值手动800和533，但它不这样的。

I also tried BitmapFactory.decodeFile(file, options) and setting the Options.outHeight and Options.outWidth values manually to 800 and 533, but it doesn't work that way.

推荐答案

否。我想有人纠正我的爱，但我接受了负载/调整你尝试过作为一个折中的方法。

No. I'd love for someone to correct me, but I accepted the load/resize approach you tried as a compromise.

下面是步骤，任何人浏览：

Here are the steps for anyone browsing:

1. 计算最大可能的 inSampleSize 仍然产生的图像比你的目标较大。
2. 使用加载图像 BitmapFactory.de codeFILE（文件，选项），传递inSampleSize作为一个选项。
3. 调整使用所需的尺寸 Bitmap.createScaledBitmap（）。

1. Calculate the maximum possible inSampleSize that still yields an image larger than your target.
2. Load the image using BitmapFactory.decodeFile(file, options), passing inSampleSize as an option.
3. Resize to the desired dimensions using Bitmap.createScaledBitmap().

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