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| | {{AppliesToAxelEsatta}} | | {{AppliesToAxelEsatta}} |
| | {{AppliesToAxelLite}} | | {{AppliesToAxelLite}} |
| | + | {{AppliesToAXEL Lite AN}} |
| | {{AppliesToSMARX AN}} | | {{AppliesToSMARX AN}} |
| | {{AppliesToAXELULite}} | | {{AppliesToAXELULite}} |
| | + | {{AppliesToAXEL ULite AN}} |
| | {{AppliesToSBCLynx}} | | {{AppliesToSBCLynx}} |
| | + | {{AppliesTo SBC Lynx AN}} |
| | {{InfoBoxBottom}} | | {{InfoBoxBottom}} |
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| | | 1.0.0 | | | 1.0.0 |
| | | February 2021 | | | February 2021 |
| − | |[[Axel_Embedded_Linux_Kit_(XELK)#XELK_3.0.1|XELK 3.0.1]] | + | |[[Axel_Embedded_Linux_Kit_(XELK)#XELK_4.0.0|XELK 4.0.0]] , [[AXEL_ULite_and_SBC_Lynx_Embedded_Linux_Kit_(XUELK)#XUELK_2.0.1.2F2.0.2.2F2.0.3|XUELK 2.0.3]] |
| | |- | | |- |
| | |} | | |} |
| | | | |
| | ==Introduction== | | ==Introduction== |
| − | In certain situations, it is necessary and/or convenient to grab a screenshot of the full display from the framebuffer directly, for example for debugging purposes or documentation. By using the well-known [https://imagemagick.org/ ImageMagick suite], this job can be accomplished straightforwardly. This Application Note (AN) shows how to use it on a system running a XELK-based Yocto Linux distribution. | + | In certain situations, it is necessary and/or convenient to grab a screenshot of the full display from the framebuffer directly, for example for debugging purposes or documentation. <code>fbgrab</code> is a small utility that can be used for this job. This Application Note (AN) shows how to use it on a system running a XELK-based Yocto Linux distribution. |
| | | | |
| − | ==Installing <code>ImageMagick convert</code>== | + | ==Installing <code>fbgrab</code>== |
| − | Assuming that root file system provides the [[XELK-AN-003:_Package_Management_with_Yocto|<code>smart</code> tool]] and it is set up properly, the <code>ImageMagick</code> package can be installed as follows: | + | Assuming that root file system provides the [[XELK-AN-003:_Package_Management_with_Yocto|<code>smart</code> tool]], the <code>fbgrab</code> utility can be installed as follows: |
| | | | |
| | <pre class="board-terminal"> | | <pre class="board-terminal"> |
| − | root@sznpc:~# smart install imagemagick
| |
| − | Loading cache...
| |
| − | Updating cache... ###################################################################################### [100%]
| |
| | | | |
| − | Computing transaction...
| |
| − |
| |
| − | Installing packages (11):
| |
| − | imagemagick-6.9.2-r0@cortexa9hf_neon libice6-1:1.0.9-r0@cortexa9hf_neon libxau6-1:1.0.8-r0@cortexa9hf_neon libxext6-1:1.3.3-r0@cortexa9hf_neon
| |
| − | lcms-2.7-r0@cortexa9hf_neon libsm6-1:1.2.2-r0@cortexa9hf_neon libxcb1-1.11.1-r0@cortexa9hf_neon libxt6-1:1.1.5-r0@cortexa9hf_neon
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| − | libfftw-3.3.4-r0@cortexa9hf_neon libx11-6-1:1.6.3-r0@cortexa9hf_neon libxdmcp6-1:1.1.2-r0@cortexa9hf_neon
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| − |
| |
| − | 3.8MB of package files are needed. 8.7MB will be used.
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| − |
| |
| − | Confirm changes? (Y/n): y
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| − |
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| − | [ 410.232039] rtc-pcf2127-i2c 1-0051: low voltage detected, check/replace RTC battery.
| |
| − | Fetching packages...
| |
| − | -> http://yocto.dave.eu/xelk-3.0.0/cortexa9hf_neon/libxcb1-1.11.1-r0.cortexa9hf_neon.rpm
| |
| − | -> http://yocto.dave.eu/xelk-3.0.0/cortexa9hf_neon/libice6-1.0.9-r0.cortexa9hf_neon.rpm
| |
| − | libice6-1.0.9-r0.cortexa9hf_neon.rpm ###################################################################################### [ 9%]
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| − | libxcb1-1.11.1-r0.cortexa9hf_neon.rpm ###################################################################################### [ 18%]
| |
| − | -> http://yocto.dave.eu/xelk-3.0.0/cortexa9hf_neon/lcms-2.7-r0.cortexa9hf_neon.rpm
| |
| − | -> http://yocto.dave.eu/xelk-3.0.0/cortexa9hf_neon/libsm6-1.2.2-r0.cortexa9hf_neon.rpm
| |
| − | libsm6-1.2.2-r0.cortexa9hf_neon.rpm ###################################################################################### [ 27%]
| |
| − | -> http://yocto.dave.eu/xelk-3.0.0/cortexa9hf_neon/libxt6-1.1.5-r0.cortexa9hf_neon.rpm
| |
| − | libxt6-1.1.5-r0.cortexa9hf_neon.rpm ###################################################################################### [ 36%]
| |
| − | -> http://yocto.dave.eu/xelk-3.0.0/cortexa9hf_neon/libxext6-1.3.3-r0.cortexa9hf_neon.rpm
| |
| − | libxext6-1.3.3-r0.cortexa9hf_neon.rpm ###################################################################################### [ 45%]
| |
| − | -> http://yocto.dave.eu/xelk-3.0.0/cortexa9hf_neon/libxdmcp6-1.1.2-r0.cortexa9hf_neon.rpm
| |
| − | libxdmcp6-1.1.2-r0.cortexa9hf_neon.rpm ###################################################################################### [ 54%]
| |
| − | -> http://yocto.dave.eu/xelk-3.0.0/cortexa9hf_neon/libxau6-1.0.8-r0.cortexa9hf_neon.rpm
| |
| − | libxau6-1.0.8-r0.cortexa9hf_neon.rpm ###################################################################################### [ 63%]
| |
| − | lcms-2.7-r0.cortexa9hf_neon.rpm ###################################################################################### [ 72%]
| |
| − | -> http://yocto.dave.eu/xelk-3.0.0/cortexa9hf_neon/libx11-6-1.6.3-r0.cortexa9hf_neon.rpm
| |
| − | -> http://yocto.dave.eu/xelk-3.0.0/cortexa9hf_neon/libfftw-3.3.4-r0.cortexa9hf_neon.rpm
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| − | libfftw-3.3.4-r0.cortexa9hf_neon.rpm ###################################################################################### [ 81%]
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| − | libx11-6-1.6.3-r0.cortexa9hf_neon.rpm ###################################################################################### [ 90%]
| |
| − | -> http://yocto.dave.eu/xelk-3.0.0/cortexa9hf_neon/imagemagick-6.9.2-r0.cortexa9hf_neon.rpm
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| − | imagemagick-6.9.2-r0.cortexa9hf_neon.rpm ###################################################################################### [100%]
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| − |
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| − |
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| − | Committing transaction...
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| − | Preparing... ###################################################################################### [ 0%]
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| − | 1:Installing libice6 ###################################################################################### [ 9%]
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| − | 2:Installing lcms ###################################################################################### [ 18%]
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| − | 3:Installing libxdmcp6 ###################################################################################### [ 27%]
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| − | 4:Installing libfftw ###################################################################################### [ 36%]
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| − | 5:Installing libxau6 ###################################################################################### [ 45%]
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| − | 6:Installing libsm6 ###################################################################################### [ 54%]
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| − | 7:Installing libxcb1 ###################################################################################### [ 63%]
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| − | 8:Installing libx11-6 ###################################################################################### [ 72%]
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| − | 9:Installing libxt6 ###################################################################################### [ 81%]
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| − | 10:Installing libxext6 ###################################################################################### [ 90%]
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| − | 11:Installing imagemagick ###################################################################################### [100%]
| |
| − | Output from imagemagick-6.9.2-r0@cortexa9hf_neon:
| |
| − | update-alternatives: Linking /usr/bin/animate to /usr/bin/animate.im6
| |
| − | update-alternatives: Linking /usr/bin/compare to /usr/bin/compare.im6
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| − | update-alternatives: Linking /usr/bin/composite to /usr/bin/composite.im6
| |
| − | update-alternatives: Linking /usr/bin/conjure to /usr/bin/conjure.im6
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| − | update-alternatives: Linking /usr/bin/convert to /usr/bin/convert.im6
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| − | update-alternatives: Linking /usr/bin/display to /usr/bin/display.im6
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| − | update-alternatives: Linking /usr/bin/identify to /usr/bin/identify.im6
| |
| − | update-alternatives: Linking /usr/bin/import to /usr/bin/import.im6
| |
| − | update-alternatives: Linking /usr/bin/mogrify to /usr/bin/mogrify.im6
| |
| − | update-alternatives: Linking /usr/bin/montage to /usr/bin/montage.im6
| |
| − | update-alternatives: Linking /usr/bin/stream to /usr/bin/stream.im6
| |
| | </pre> | | </pre> |
| | | | |
| | ==Capturing screenshots== | | ==Capturing screenshots== |
| − | The following examples refer to a system using a 1024x600 24bpp framebuffer, which is mapped to <code>/dev/fb0</code>. | + | The following examples refer to a system using a 1024x768 16bpp framebuffer, which is mapped to <code>/dev/fb0</code>. |
| | | | |
| | When the display shows the image to be captured, to grab a "raw" screenshot and save it to file, issue the following command: | | When the display shows the image to be captured, to grab a "raw" screenshot and save it to file, issue the following command: |
| | <pre class="board-terminal"> | | <pre class="board-terminal"> |
| − | root@sznpc:~# dd if=/dev/fb0 of=screenshot.raw
| + | cat /dev/fb0 > test.fb |
| − | 4800+0 records in
| |
| − | 4800+0 records out
| |
| | </pre> | | </pre> |
| | | | |
| − | Then convert the raw data to a PNG image file by running the following command: | + | Then convert the raw data to a PNG image file, run the following command: |
| | <pre class="board-terminal"> | | <pre class="board-terminal"> |
| − | root@sznpc:~# convert -size 1024x600 -depth 8 rgba:screenshot.raw screen0.png
| + | ./fbgrab -w 1024 -h 768 -b 16 -l 1024 -f test.fb test.png |
| | + | Converting image from 16 |
| | + | Now writing PNG file (compression -1) |
| | </pre> | | </pre> |
| | | | |
| − | Alternatively, if the <code>convert</code> utility can not be installed onto the target's root filesystem, the raw data file <code>screenshot.raw</code> can be copied to a Linux host where <code>convert</code> is available. | + | Alternatively, the raw data file <code>test.fb</code> can be copied to a Linux host where <code>fbgrab</code> is installed. |
| | | | |
| − | It is also worth remembering that, if the screen parameters such as resolution or pixel depth are unknown, the [http://spblinux.de/2.0/doc/fbset.html <code>fbset</code> tool] can be used to display them: | + | It is worth remembering that, if the resolution and/or pixel depth are unknown, the [http://spblinux.de/2.0/doc/fbset.html <code>fbset</code> tool] can be used to display such parameters: |
| | <pre class="board-terminal"> | | <pre class="board-terminal"> |
| − | root@sznpc:~# fbset
| |
| − |
| |
| − | mode "1024x600-67"
| |
| − | # D: 51.201 MHz, H: 43.538 kHz, V: 67.085 Hz
| |
| − | geometry 1024 600 1024 600 32
| |
| − | timings 19531 104 43 24 20 5 5
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| − | accel false
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| − | rgba 8/16,8/8,8/0,8/24
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| − | endmode
| |
| | </pre> | | </pre> |
| − | The numbers following <code>geometry</code> indicate the resolution (1024x600) and the bits required to represent a pixel (32). The last line tells the pixel format (RGBA). In this case, 8 bits are used for each channel (reg, green, blue, and alpha) resulting in 32 bits combined. That is why the <code>depth</code> parameter of <code>convert</code> was set to 8 and the format was set to <code>rgba</code>.
| |
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