[Atrix 4G Android Development] NFHimself:
Hi,

I had posted this in the Q&A thread, thought I would post it here as well.

Glossary:

boot logo: the static image you see when you turn on the phone.

boot animation: a series of pics in a zip file that are displayed after the boot logo.

Hi,

If you want to change the boot logo, you just fastboot flash logo logo.bin. It's mmcblk0p8.

The format is a constant string, 4 bytes, "SOL:" followed by 4 zero bytes, followed by 4 bytes for the width, 540, 4 bytes for the height 960, and the raw data of the image. Each pixel is 2 bytes, it's 565 format.

save a png as 540x960 called logo.png

$ convert -depth 8 logo.png rgb:logo.raw

$ ./rgb2565 < logo.raw > temp.bin

$ cat logo-heaader.bin temp.bin > logo.bin

$ sudo ./moto-fastboot flash logo logo.bin

Here is the source to rgb2565:

/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#define to565(r,g,b) \
((((r) >> 3) << 11) | (((g) >> 2) << 5) | ((b) >> 3))

#define from565_r(x) ((((x) >> 11) & 0x1f) * 255 / 31)
#define from565_g(x) ((((x) >> 5) & 0x3f) * 255 / 63)
#define from565_b(x) (((x) & 0x1f) * 255 / 31)

void to_565_raw(void)
{
unsigned char in[3];
unsigned short out;

while(read(0, in, 3) == 3) {
out = to565(in[0],in[1],in[2]);
write(1, &out, 2);
}
return;
}

void to_565_raw_dither(int width)
{
unsigned char in[3];
unsigned short out;
int i = 0;
int e;

int* error = malloc((width+2) * 3 * sizeof(int));
int* next_error = malloc((width+2) * 3 * sizeof(int));
memset(error, 0, (width+2) * 3 * sizeof(int));
memset(next_error, 0, (width+2) * 3 * sizeof(int));
error += 3; // array goes from [-3..((width+1)*3+2)]
next_error += 3;

while(read(0, in, 3) == 3) {
int r = in[0] + error[i*3+0];
int rb = (r < 0) ? 0 : ((r > 255) ? 255 : r);

int g = in[1] + error[i*3+1];
int gb = (g < 0) ? 0 : ((g > 255) ? 255 : g);

int b = in[2] + error[i*3+2];
int bb = (b < 0) ? 0 : ((b > 255) ? 255 : b);

out = to565(rb, gb, bb);
write(1, &out, 2);

#define apply_error(ch) { \
next_error[(i-1)*3+ch] += e * 3 / 16; \
next_error[(i)*3+ch] += e * 5 / 16; \
next_error[(i+1)*3+ch] += e * 1 / 16; \
error[(i+1)*3+ch] += e - ((e*1/16) + (e*3/16) + (e*5/16)); \
}

e = r - from565_r(out);
apply_error(0);

e = g - from565_g(out);
apply_error(1);

e = b - from565_b(out);
apply_error(2);

#undef apply_error

++i;
if (i == width) {
// error <- next_error; next_error <- 0
int* temp = error; error = next_error; next_error = temp;
memset(next_error, 0, (width+1) * 3 * sizeof(int));
i = 0;
}
}

free(error-3);
free(next_error-3);

return;
}

void to_565_rle(void)
{
unsigned char in[3];
unsigned short last, color, count;
unsigned total = 0;
count = 0;

while(read(0, in, 3) == 3) {
color = to565(in[0],in[1],in[2]);
if (count) {
if ((color == last) && (count != 65535)) {
count++;
continue;
} else {
write(1, &count, 2);
write(1, &last, 2);
total += count;
}
}
last = color;
count = 1;
}
if (count) {
write(1, &count, 2);
write(1, &last, 2);
total += count;
}
fprintf(stderr,"%d pixels\n",total);
}

int main(int argc, char **argv)
{
if ((argc == 2) && (!strcmp(argv[1],"-rle"))) {
to_565_rle();
} else {
if (argc > 2 && (!strcmp(argv[1], "-w"))) {
to_565_raw_dither(atoi(argv[2]));
} else {
to_565_raw();
}
}
return 0;
}

See example logo.bin attached.

Cheers!​