CODEWITHSUNDEEP
windowshighlight
tt9
tt9

Reputation: 6069

How does modifying text highlighting work?

We are all familiar with text highlighting. You hover over any "text" in any application on your Windows OS, your cursor changes into an I-Beam, and you can click and drag across the text to Highlight it. This highlighted text can be copied to the clipboard for later use.

Some applications modify the default highlighting behavior by changing color, opacity, or even shape. Some applications allow for column selection (e.g. Visual Studio "alt-click-drag" creates box like highlighting)

I have scoured the depths of the internet, but I can't seem to find a solid source of information that would explain how one would modify the behavior of text highlighting.

How would I implement column/block text selection, and modifying the appearance of the highlighted text in a compiled application.

Upvotes: 1

Views: 61

Answers (2)

CodeCaster
CodeCaster

Reputation: 151586

I'm not sure what you mean with the web application part of your question. A web application is some HTML, JS and CSS that make the browser interact with your system. Any custom selection (coloring) logic that the web application provides, has to be implemented by the browser.

Also you have to realize that "(text) selection" is an rather virtual principle. An application can just render a colored shape (like a blue rectangle) and copy something to the clipboard when it receives a WM_COPY message.

Windows provides in basic substring selection functionality for (rich) edit controls (i.e. start and end position), but for something custom like column selection, custom code is required.

Read more about this in Making a rectangular selection in a RichTextBox with Alt-Left-Mouse sweep?.

Upvotes: 1

Adrian McCarthy
Adrian McCarthy

Reputation: 47952

Since applications can do this in various custom ways, there is no single solution to change how all of them style text selections.

Many will rely on the current color scheme (using GetSysColor) to determine the highlight colors. So you could modify the scheme and maybe affect the colors used for many applications.

To do this programmatically, you would use SetSysColors to change the COLOR_HIGHLIGHT and COLOR_HIGHLIGHTTEXT values.

Other applications might rely on the current theme (using GetThemeColor). To affect those you'd have to select a different theme that has the colors (and perhaps other styling choices) that you want.

A lot of apps use their own hard-coded color schemes, so you won't be able to programmatically at all.

Upvotes: 2

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