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Showing posts from May, 2022

Use GIMP to change background color of an image

Image
Contents [ hide ] Step 1: Open image Chinese version: Zhihu Change the backgroud color of this image: The image is from Internet, if it infringes copyright, please leave a comment and I'll delete it. Step 1: Open image File -- Open, to open an image: Step 2: Choose the background Click "Fuzzy Select Tool" and click the background to choose it. You'd better use single color background. If there are many colors in the background, press "shift" and click the color you want to change to increase the selected area, press "alt" and click the color you don't want to change to decrease the selected area. Step 3: Add alpha channel Right-click the image -- Layer -- Transparency -- Add Alpha Channel: Step 4: Remove the background Right-click the image -- Edit -- Clear: Step 5: Add a new layer Click "Creat a new layer and ...

Do math typesetting in one markdown file using KaTeX

Contents [ hide ] 1. Accents Chinese version: Zhihu Use Vs Code and extension Markdown Preview Enhanced (by Yiyi Wang) you can preview math typesetting in markdown file using KaTeX, see Math . By the way, I use Markdown All in One (by Yu Zhang) to creat table of contents and export markdown to html, Markdown Footnote (by Mai Hou) to automatically add footnotes and markdown-index (by legendmohe) to automatically add serial numbers on titles. Here I introduce some basic fomulas most used in Calculus, for more information, see KaTeX . The contents in every section are: code, preview. 1. Accents 1.1. Prime $ f'(x) $ f ′ ( x ) f'(x) f ′ ( x ) 1.2. Vector $ \vec {a} $ a ⃗ \vec {a} a $ \overrightarrow {PP_0} $ P P 0 → \overrightarrow {PP_0} P P 0 ​ ​ 1.3. Hat $ \hat{\theta} $ θ ^ \hat{\theta} θ ^ $ \widehat{ac} $ a c ^ \widehat{ac} a c 2....