我的目标是能够键入一个单词命令并从通过 USB 连接的已 root 的 Nexus One 获取屏幕截图。
到目前为止，我可以获取帧缓冲区，我相信这是一个 32位 xRGB888 原始图像，通过以下方式进行提取：
adb pull /dev/graphics/fb0 fb0
不过，从那里开始，我很难将它转换为png格式。我正在尝试使用ffmpeg进行转换，如下所示：
ffmpeg -vframes 1 -vcodec rawvideo -f rawvideo -pix_fmt rgb8888 -s 480x800 -i fb0 -f image2 -vcodec png image.png
这会生成一张可爱的紫色图像，其中有些部分模糊地类似于屏幕，但并不是完全清晰的截图。
ICS的一个极为简单的解决方案是从命令行使用以下内容：
adb shell /system/bin/screencap -p /sdcard/screenshot.png
adb pull /sdcard/screenshot.png screenshot.png
这将会在当前目录保存screenshot.png文件。
在一个运行4.0.3的三星Galaxy SII & SII上进行过测试。
实际上，还有一种非常简单的方法可以从你的Android设备中抓取截图：编写一个像这样的简单脚本1.script：
# Imports the monkeyrunner modules used by this program
from com.android.monkeyrunner import MonkeyRunner, MonkeyDevice
# Connects to the current device, returning a MonkeyDevice object
device = MonkeyRunner.waitForConnection()
# Takes a screenshot
result = device.takeSnapshot()
# Writes the screenshot to a file
result.writeToFile('1.png','png')
然后调用 monkeyrunner 1.script。
看起来，N1的帧缓冲使用RGB32编码（每像素32位）。
这是我使用ffmpeg的脚本：
adb pull /dev/graphics/fb0 fb0
dd bs=1920 count=800 if=fb0 of=fb0b
ffmpeg -vframes 1 -vcodec rawvideo -f rawvideo -pix_fmt rgb32 -s 480x800 -i fb0b -f image2 -vcodec png fb0.png
另一种方法是从这里描述的ADP1方法得出的 http://code.lardcave.net/entries/2009/07/27/132648/
adb pull /dev/graphics/fb0 fb0
dd bs=1920 count=800 if=fb0 of=fb0b
python rgb32torgb888.py <fb0b >fb0b.888
convert -depth 8 -size 480x800 RGB:fb0b.888 fb0.png
Python脚本 'rgb32torgb888.py':
import sys
while 1:
colour = sys.stdin.read(4)
if not colour:
break
sys.stdout.write(colour[2])
sys.stdout.write(colour[1])
sys.stdout.write(colour[0])
使用我的HTC Hero（因此从480x800调整为320x480），如果我使用rgb565而不是8888，则可以正常工作：
ffmpeg -vframes 1 -vcodec rawvideo -f rawvideo -pix_fmt rgb565 -s 320x480 -i fb0 -f image2 -vcodec png image.png
adb shell screencap -p | dos2unix > screen.png
我认为到目前为止所有的帧缓冲都是RGB 565，而不是888。
adb shell screencap -p | perl -pe 's/\x0D\x0A/\x0A/g' > screen.png
screen.png之前给出路径或目录。希望我的脚本能对你有所帮助。我在我的Galaxy Tab上使用它，它运行得非常完美，但是你可以更改默认分辨率。不过需要使用“zsh” shell：
#!/bin/zsh
# These settings are for the galaxy tab.
HRES=600
VRES=1024
usage() {
echo "Usage: $0 [ -p ] outputfile.png"
echo "-- takes screenshot off your Galaxy Tab Android phone."
echo " -p: portrait mode"
echo " -r X:Y: specify resolution, e.g. -r 480:640 specifies that your cellphone has 480x640 resolution."
exit 1
}
PORTRAIT=0 # false by default
umask 022
[[ ! -w . ]] && {
echo "*** Error: current directory not writeable."
usage
}
[[ ! -x $(which mogrify) ]] && {
echo "*** Error: ImageMagick (mogrify) is not in the PATH!"
usage
}
while getopts "pr:" myvar
do
[[ "$myvar" == "p" ]] && PORTRAIT=1
[[ "$myvar" == "r" ]] && {
testhres="${OPTARG%%:*}" # remove longest-matching :* from end
testvres="${OPTARG##*:}" # remove longest-matchung *: from beginning
if [[ $testhres == <0-> && $testvres == <0-> ]] # Interval: from 0 to infinite. Any value would be: <->
then
HRES=$testhres
VRES=$testvres
else
echo "Error! One of these values - '${testhres}' or '${testvres}' - is not numeric!"
usage
fi
}
done
shift $((OPTIND-1))
[[ $# < 1 ]] && usage
outputfile="${1}"
blocksize=$((HRES*4))
count=$((VRES))
adb pull /dev/graphics/fb0 fb0.$$
/bin/dd bs=$blocksize count=$count if=fb0.$$ of=fb0b.$$
/usr/bin/ffmpeg -vframes 1 -vcodec rawvideo -f rawvideo -pix_fmt rgb32 -s ${VRES}x${HRES} -i fb0b.$$ -f image2 -vcodec png "${outputfile}"
if (( ${PORTRAIT} ))
then
mogrify -rotate 270 "${outputfile}"
else
mogrify -flip -flop "${outputfile}"
fi
/bin/rm -f fb0.$$ fb0b.$$
我认为rgb32torgb888.py应该是这样的：
sys.stdout.write(colour[0])
sys.stdout.write(colour[1])
sys.stdout.write(colour[2])
#!/bin/bash
#
# adb-screenshot - simple script to take screenshots of android devices
#
# Requires: 'ffmpeg' and 'adb' to be somewhere in the PATH
#
# Author: Kevin C. Krinke <kevin@krinke.ca>
# License: Public Domain
# globals / constants
NAME=$(basename $0)
TGT=~/Desktop/${NAME}.png
SRC=/sdcard/${NAME}.png
TMP=/tmp/${NAME}.$$
RAW=/tmp/${NAME}.raw
FFMPEG=$(which ffmpeg)
ADB=$(which adb)
DD=$(which dd)
USB_DEVICE=""
# remove transitory files if exist
function cleanup () {
[ -f "${RAW}" ] && rm -f "${RAW}"
[ -f "${TMP}" ] && rm -f "${TMP}"
[ -z "$1" ] && die "aborting process now."
exit 0
}
# exit with an error
function die () {
echo "Critical Error: $@"
exit 1
}
# catch all signals and cleanup / dump
trap cleanup \
SIGHUP SIGINT SIGQUIT SIGILL SIGTRAP SIGABRT SIGEMT SIGFPE \
SIGKILL SIGBUS SIGSEGV SIGSYS SIGPIPE SIGALRM SIGTERM SIGURG \
SIGSTOP SIGTSTP SIGCONT SIGCHLD SIGTTIN SIGTTOU SIGIO SIGXCPU \
SIGXFSZ SIGVTALRM SIGPROF SIGWINCH SIGINFO SIGUSR1 SIGUSR2
# adb is absolutely required
[ -x "${ADB}" ] || die "ADB is missing!"
# cheap getopt
while [ $# -gt 0 ]
do
case "$1" in
"-h"|"--help")
echo "usage: $(basename $0) [-h|--help] [-s SERIAL] [/path/to/output.png]"
exit 1
;;
"-s")
[ -z "$2" ] && die "Missing argument for option \"-s\", try \"${NAME} --help\""
HAS_DEVICE=$(${ADB} devices | grep "$2" )
[ -z "${HAS_DEVICE}" ] && die "No device found with serial $2"
USB_DEVICE="$2"
;;
*)
[ -n "$1" -a -d "$(dirname $1)" ] && TGT="$1"
;;
esac
shift
done
# prep target with fire
[ -f "${TGT}" ] && rm -f "${TGT}"
# tweak ADB command line
if [ -n "${USB_DEVICE}" ]
then
ADB="$(which adb) -s ${USB_DEVICE}"
fi
# calculate resolution
DISPLAY_RAW=$(${ADB} shell dumpsys window)
HRES=$(echo "${DISPLAY_RAW}" | grep SurfaceWidth | head -1 | perl -pe 's/^.*\bSurfaceWidth\:\s*(\d+)px\b.*$/$1/')
VRES=$(echo "${DISPLAY_RAW}" | grep SurfaceHeight | head -1 | perl -pe 's/^.*\bSurfaceHeight\:\s*(\d+)px\b.*$/$1/')
RES=${HRES}x${VRES}
# check for screencap binary
HAS_SCREENCAP=$(${ADB} shell "[ -x /system/bin/screencap ] && echo 1 || echo 0" | perl -pe 's/\D+//g')
if [ "$HAS_SCREENCAP" == "1" ]
then # use screencap to get the image easy-peasy
echo -n "Getting ${RES} screencap... "
( ${ADB} shell /system/bin/screencap ${SRC} 2>&1 ) > /dev/null
[ "$?" != "0" ] && die "Failed to execute screencap"
( ${ADB} pull ${SRC} ${TMP} 2>&1 ) > /dev/null
[ "$?" != "0" ] && die "Failed to pull png image"
( ${ADB} shell rm ${SRC} 2>&1 ) > /dev/null
[ "$?" != "0" ] && die "Failed to remove png image"
mv ${TMP} ${TGT}
echo "wrote: ${TGT}"
else # fetch a framebuffer snapshot
# ffmpeg is only needed if device is pre-ICS
[ -x "${FFMPEG}" ] || die "FFMPEG is missing!"
[ -x "${DD}" ] || die "DD is missing!"
echo -n "Getting ${RES} framebuffer... "
( ${ADB} pull /dev/graphics/fb0 ${RAW} 2>&1 ) > /dev/null
[ "$?" != "0" ] && die "Failed to pull raw image data"
# calculate dd parameters
COUNT=$((HRES*4))
BLOCKSIZE=$((VRES))
( ${DD} bs=${BLOCKSIZE} count=${COUNT} if=${RAW} of=${TMP} 2>&1 ) > /dev/null
[ "$?" != "0" ] && die "Failed to realign raw image data"
( ${FFMPEG} -vframes 1 -vcodec rawvideo -f rawvideo -pix_fmt rgb32 -s ${RES} -i ${TMP} -f image2 -vcodec png ${TGT} 2>&1 ) > /dev/null
[ "$?" != "0" ] && die "Failed to encode PNG image"
echo "wrote: ${TGT}"
fi
# exit app normal
cleanup 1
adb shell screencap -p | uuencode -m - | uudecode -o out.png（需要Linux和uudecode，但base64也可以使用） - ce4