blog/imagemagick-use-case-process-ltspice-schematic-images/imagemagick-use-case-process-ltspice-schematic-images.md (6202B)
1 %% 2 title: "ImageMagick Use Case: Process LTspice Schematic Images" 3 date: "19-Nov-2024" 4 %% 5 6 # ImageMagick Use Case: Process LTspice Schematic Images 7 8 In this post I explain how I managed to simplify to a 'one-liner' the series of 9 steps involved in exporting and processing the image of an LTSpice schematic for 10 further use in a report paper or any similar document. 11 12 > ***TL;DR*** 13 > 14 > Copy to clipboard the current view of the schematic in LTSpice: `right click > 15 > view > copy image to clipboard`, then, using xclip, pipe the content of the 16 > clipboard to magick and save the image with name `schematic.png`, in black and 17 > white (`-colorspace grey`) and cropped to the contents of the image (`-trim`) 18 > 19 > ```console 20 > $ xclip -selection clipboard -t image/bmp -o | magick - -colorspace grey -trim schematic.png 21 > ``` 22 > <!--`--> 23 24 ## Getting an image of the schematic from LTSpice 25 26 First we copy the current schematic view in LTSpice to the clipboard with: 27 `right click on an empty space of the schematic > view > copy image to 28 clipboard`. 29 30  31 32 Others may just take a screenshot of the schematic, this is also a valid way of 33 getting an image of the schematic but as we'll see later it's more practical to 34 just copy the image to clipboard since it doesn't require the creation of a new 35 temporary file. 36 37 ## Previous Procedure 38 39 <!-- 40 First we copy the current schematic view of LTSpice to clipboard with: `right 41 click on an empty space of the schematic > view > copy image to clipboard`. 42 43  44 45 Other may just take a screenshot of the schematic, this is also a valid way of 46 getting an image of the schematic but in my experience it's better, and simpler, 47 to copy the image to clipboard 48 --> 49 50 After copying the image to the clipboard from LTSpice as seen in the previous 51 section, just using a GUI program like gimp, paste the image from the clipboard, 52 crop the image, apply black and white filters, etc; finally export the image. 53 54 This procedure looks simple, but when doing it with multiple schematics it turns 55 tedious. In the current procedure the steps after copying the image shrinks to a 56 one-liner (a single line containing one or more chained commands). 57 58 ## Current Procedure 59 60 <!-- 61 Copying the schematic image from LTSpice is the same as the previous way, the 62 steps that change are the following ones which involve getting the image from 63 the clipboard, processing it and finally exporting it to a file. In this new 64 procedure we use a series of chained command line commands to obtain that. 65 --> 66 67 Instead of using a GUI program after copying the image to the clipboard from 68 LTSpice, we use a series of command line tools to process and save the image, in 69 particular, xclip to manage the clipboard contents (X session) and ImageMagick 70 to process the image. 71 72 ### Getting the image from the clipboard 73 74 To get the image from the clipboard we use xclip (xclip works for an X session, 75 if you are using Wayland you may use [wl-clipboard](https://github.com/bugaevc/wl-clipboard) 76 which it may have similar commands to the ones seen on this post). 77 78 <!-- 79 Then we can query the format of the copied image by specifying the `TARGETS` 80 target to xclip, as follows: 81 82 After copying the image from LTSpice, you may query the supoorted image formats 83 of that image, you can do that 84 --> 85 86 After copying the image from LTSpice, you may query the supported image formats 87 of the clipboards contents, you can do that by providing the `TARGETS` to the 88 target flag `-t` as show next. 89 90 ```console 91 $ xclip -selection clipboard -t TARGETS -o 92 PIXMAP 93 image/bmp 94 TARGETS 95 MULTIPLE 96 TIMESTAMP 97 ``` 98 99 Notice that we provide the `-selection clipboard` flag, this selects the 100 clipboard named `clipboard` (there is also `primary` and `secondary`). In this 101 case we use LTSpice running on wine so it may use a different clipboard for 102 other installations. 103 104 Specifying the `image/bmp` target to xclip and no filename to the output flag 105 `-o`, will result in xclip printing the binary data to standard output (this 106 will probably mess the terminal). By piping the binary data to a file, as shown 107 next, we can make sure if the data is a bitmap formatted image. 108 109 ```console 110 $ xclip -selection clipboard -t image/bmp -o > schematic_raw 111 ``` 112 113 Executing the `file` command on the new file `schematic_raw` reveals that 114 effectively it is a bitmap file. 115 116 ```console 117 $ file schematic_raw 118 schematic_raw: PC bitmap, Windows 3.x format, 1916 x 966 x 32, 3 compression, image size 7403424, cbSize 7403490, bits offset 66 119 ``` 120 121 The raw schematic image, in bitmap format, looks exactly as shown in the LTSpice 122 schematic view. 123 124  125 126 The next step is to convert it to black and white, trim the white margins and 127 finally convert it to png format. 128 129 ### Processing the image using ImageMagick 130 131 Instead of piping the output of the xclip command to a file, we pipe the binary 132 data to ImageMagick appending a single dash `-` to tell magick to read from 133 standard input. To apply the desired effects on the image we also append the 134 flag `-colorspace grey`, to make the image black and white, the flag `-trim`, 135 to crop the image to the content, and finally we save the resulting image in png 136 format by appending the extension to the output file name (for example 137 `schematic.png`). 138 139 ```console 140 $ xclip -selection clipboard -t image/bmp -o | magick - -colorspace grey -trim schematic.png 141 ``` 142 143 The final image results as follows 144 145  146 147 ImageMagick can also read from a file, for example if you took a screenshot of 148 the schematic, you can process it by specifying the file name as input, instead 149 of reading from standard input. 150 151 ```console 152 $ magick schematic_screenshot.png -colorspace grey -trim schematic.png 153 ``` 154 155 <!-- 156 Simply pipe the output of the clipboard to ImageMagick and add the flag 157 `-colorspace grey`, to make the image black and white, and the flag `-trim` to 158 crop the image to the content. 159 160 output of the magick command is the following image, which is in black and 161 white plus the margins are cropped, resulting in an image ready for inserting in 162 a paper. 163 -->