In the process of tracking severe memory issues in my app, I looked at several heap dumps from my app, and most of the time I have a HUGE bitmap that I don't know of.
It takes 9.4MB, or 9,830,400 bytes, or actually a 1280x1920 image at 4 bytes per pixels.
I checked in Eclipse MAT, it is indeed a byte[9830400], that has one incoming reference which is a android.graphics.Bitmap.
I'd like to dump this to a file and try to see it. I can't understand where is it coming from. My biggest image in all my drawables is a 640x960 png, which takes less than 3MB.
I tried to use Eclipse to "copy value to file", but I think it simply prints the buffer to the file, and I don't know any image software that can read a stream of bytes and display it as a 4 bytes per pixel image.
Any idea?
Here's what I tried: dump the byte array to a file, push it to /sdcard/img, and load an activity like this:
@Override
public void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
try {
final File inputFile = new File("/sdcard/img");
final FileInputStream isr = new FileInputStream(inputFile);
final Bitmap bmp = BitmapFactory.decodeStream(isr);
ImageView iv = new ImageView(this);
iv.setImageBitmap(bmp);
setContentView(iv);
Log.d("ImageTest", "Image was inflated");
} catch (final FileNotFoundException e) {
Log.d("ImageTest", "Image was not inflated");
}
}
I didn't see anything.
Do you know how is encoded the image? Say it is stored into byte[] buffer. buffer[0] is red, buffer[1] is green, etc?
OK -- After quite some unsuccessful tries, I finally got something out of this byte array. I wrote this simple C program to convert the byte array to a Windows Bitmap file. I'm dropping the code in case somebody is interested.
I compiled this against VisualC 6.0 and gcc 3.4.4, it should work on any OS (tested on Windows, Linux and MacOS X).
#include <stdio.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>
/* Types */
typedef unsigned char byte;
typedef unsigned short uint16_t;
typedef unsigned int uint32_t;
typedef int int32_t;
/* Constants */
#define RMASK 0x00ff0000
#define GMASK 0x0000ff00
#define BMASK 0x000000ff
#define AMASK 0xff000000
/* Structures */
struct bmpfile_magic {
unsigned char magic[2];
};
struct bmpfile_header {
uint32_t filesz;
uint16_t creator1;
uint16_t creator2;
uint32_t bmp_offset;
};
struct bmpfile_dibheader {
uint32_t header_sz;
uint32_t width;
uint32_t height;
uint16_t nplanes;
uint16_t bitspp;
uint32_t compress_type;
uint32_t bmp_bytesz;
int32_t hres;
int32_t vres;
uint32_t ncolors;
uint32_t nimpcolors;
uint32_t rmask, gmask, bmask, amask;
uint32_t colorspace_type;
byte colorspace[0x24];
uint32_t rgamma, ggamma, bgamma;
};
/* Displays usage info and exits */
void usage(char *cmd) {
printf("Usage:\t%s <img_src> <img_dest.bmp> <width> <height>\n"
"\timg_src:\timage byte buffer obtained from Eclipse MAT, using 'copy > save value to file' while selecting the byte[] buffer corresponding to an android.graphics.Bitmap\n"
"\timg_dest:\tpath to target *.bmp file\n"
"\twidth:\t\tpicture width, obtained in Eclipse MAT, selecting the android.graphics.Bitmap object and seeing the object member values\n"
"\theight:\t\tpicture height\n\n", cmd);
exit(1);
}
/* C entry point */
int main(int argc, char **argv) {
FILE *in, *out;
char *file_in, *file_out;
int w, h, W, H;
byte r, g, b, a, *image;
struct bmpfile_magic magic;
struct bmpfile_header header;
struct bmpfile_dibheader dibheader;
/* Parse command line */
if (argc < 5) {
usage(argv[0]);
}
file_in = argv[1];
file_out = argv[2];
W = atoi(argv[3]);
H = atoi(argv[4]);
in = fopen(file_in, "rb");
out = fopen(file_out, "wb");
/* Check parameters */
if (in == NULL || out == NULL || W == 0 || H == 0) {
usage(argv[0]);
}
/* Init BMP headers */
magic.magic[0] = 'B';
magic.magic[1] = 'M';
header.filesz = W * H * 4 + sizeof(magic) + sizeof(header) + sizeof(dibheader);
header.creator1 = 0;
header.creator2 = 0;
header.bmp_offset = sizeof(magic) + sizeof(header) + sizeof(dibheader);
dibheader.header_sz = sizeof(dibheader);
dibheader.width = W;
dibheader.height = H;
dibheader.nplanes = 1;
dibheader.bitspp = 32;
dibheader.compress_type = 3;
dibheader.bmp_bytesz = W * H * 4;
dibheader.hres = 2835;
dibheader.vres = 2835;
dibheader.ncolors = 0;
dibheader.nimpcolors = 0;
dibheader.rmask = RMASK;
dibheader.gmask = BMASK;
dibheader.bmask = GMASK;
dibheader.amask = AMASK;
dibheader.colorspace_type = 0x57696e20;
memset(&dibheader.colorspace, 0, sizeof(dibheader.colorspace));
dibheader.rgamma = dibheader.bgamma = dibheader.ggamma = 0;
/* Read picture data */
image = (byte*) malloc(4*W*H);
if (image == NULL) {
printf("Could not allocate a %d-byte buffer.\n", 4*W*H);
exit(1);
}
fread(image, 4*W*H, sizeof(byte), in);
fclose(in);
/* Write header */
fwrite(&magic, sizeof(magic), 1, out);
fwrite(&header, sizeof(header), 1, out);
fwrite(&dibheader, sizeof(dibheader), 1, out);
/* Convert the byte array to BMP format */
for (h = H-1; h >= 0; h--) {
for (w = 0; w < W; w++) {
r = *(image + w*4 + 4 * W * h);
b = *(image + w*4 + 4 * W * h + 1);
g = *(image + w*4 + 4 * W * h + 2);
a = *(image + w*4 + 4 * W * h + 3);
fwrite(&b, 1, 1, out);
fwrite(&g, 1, 1, out);
fwrite(&r, 1, 1, out);
fwrite(&a, 1, 1, out);
}
}
free(image);
fclose(out);
}
So using this tool I was able to recognise the picture used to generate this 1280x1920 bitmap.