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Use GIMP to change the size of an image

Image
Chinese version: Zhihu You can use "Scale image" function in GIMP to change the size of an image according to pixel or millimeter. Step 1: File -- Open, open an image. Step 2: Image -- Scale Image. (The image is from Internet, if it infringes copyright, leave a comment and I'll delete it.) Step 3: First choose pixel or millimeter, then choose width and height of the image. Notice to cancle the fixed aspect ratio of original image, or the result may be a little diffirent from your expectation. Step 4: File -- Export as, change the file extenstion to what you want and the destination folder, then click Export. I just tried to scale large size to small size, you can try to scale small size to large size by yourself. By the way, you can use Crop Tool to change the size, but if the size of the original image is larger and very close to the size your want, the result may be wrong. Yo...

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....