I'm building a simple code editor to help children learn HTML. One feature I'm trying to add is that when users mouseover their rendered code (in an iframe), the corresponding HTML code in the editor is highlighted. So, for example, if a user mouses-over an image of kittens, the actual code, , would be highlighted in the editor.
Mousing-over the iframe to get the html source for that element is the easy part, which I've done (using document.elementFromPoint(e.clientX, e.clientY in the iframe itself, and posting that up to the parent) - so that's not the part I need help with. The part I can't figure out is how to search for and highlight that string of selected code in the code editor.
I'm using Codemirror 6 for this project, as it seems as it will give me the most flexibility to create such a feature. However, as a Codemirror 6 novice, I'm struggling with the documentation to find out where I should start. It seems like the steps I need to complete to accomplish this are:
Search for a range in the editor's text that matches a string (ie.'<img src="kittens.gif"').
Highlight that range in the editor.
Can anyone out there give me some advice as to where in the Codemirror 6 API I should look to start implementing this? It seems like it should be easy, but my unfamiliarity with the Codemirror API and the terse documentation is making this difficult.
1. Search for a range in the editor's text that matches a string (ie.'<img src="kittens.gif"').
You can use SearchCursor class (iterator) to get the character's range where is located the DOM element in your editor.
// the import for SearchCursor class
import {SearchCursor} from "#codemirror/search"
// your editor's view
let main_view = new EditorView({ /* your code */ });
// will create a cursor based on the doc content and the DOM element as a string (outerHTML)
let cursor = new SearchCursor(main_view.state.doc, element.outerHTML);
// will search the first match of the string element.outerHTML in the editor view main_view.state.doc
cursor.next()
// display the range where is located your DOM element in your editor
console.log(cursor.value);
2. Highlight that range in the editor.
As described in the migration documentation here, marked text is replace by decoration. To highlight a range in the editor with codemirror 6, you need to create one decoration and apply it in a dispatch on your view. This decoration need to be provide by an extension that you add in the extensions of your editor view.
// the import for the 3 new classes
import {StateEffect, StateField} from "#codemirror/state"
import {Decoration} from "#codemirror/view"
// code mirror effect that you will use to define the effect you want (the decoration)
const highlight_effect = StateEffect.define();
// define a new field that will be attached to your view state as an extension, update will be called at each editor's change
const highlight_extension = StateField.define({
create() { return Decoration.none },
update(value, transaction) {
value = value.map(transaction.changes)
for (let effect of transaction.effects) {
if (effect.is(highlight_effect)) value = value.update({add: effect.value, sort: true})
}
return value
},
provide: f => EditorView.decorations.from(f)
});
// this is your decoration where you can define the change you want : a css class or directly css attributes
const highlight_decoration = Decoration.mark({
// attributes: {style: "background-color: red"}
class: 'red_back'
});
// your editor's view
let main_view = new EditorView({
extensions: [highlight_extension]
});
// this is where the change takes effect by the dispatch. The of method instanciate the effect. You need to put this code where you want the change to take place
main_view.dispatch({
effects: highlight_effect.of([highlight_decoration.range(cursor.value.from, cursor.value.to)])
});
Hope it will help you to implement what you want ;)
Have a look at #codemirror/search.
Specifically, the source code implementation of Selection Matching may be of use for you to adapt.
It uses Decoration.mark over a range of text.
You can use SearchCursor to iterate over ranges that match your pattern (or RegExpCursor)
Use getSearchCursor, something like this:
var cursor = cmEditor.getSearchCursor(keyword , CodeMirror.Pos(cmEditor.firstLine(), 0), {caseFold: true, multiline: true});
if(cursor.find(false)){ //move to that position.
cmEditor.setSelection(cursor.from(), cursor.to());
cmEditor.scrollIntoView({from: cursor.from(), to: cursor.to()}, 20);
}
Programmatically search and select a keyword
Take a look at getSearchCursor source code it it give some glow about how it works and its usage.
So use getSearchCursor for finding text and optionally use markText for highlighting text because you can mark text with setSelection method of editor.
Selection Marking Demo
var editor = CodeMirror.fromTextArea(document.getElementById("code"), {
lineNumbers: true,
styleSelectedText: true
});
editor.markText({line: 6, ch: 26}, {line: 6, ch: 42}, {className: "styled-background"});
And it seem this is what you are looking for:
codemirror: search and highlight multipule words without dialog
RegExpCursor is another option that you can use:
new RegExpCursor(
text: Text,
query: string,
options?: {ignoreCase?: boolean},
from?: number = 0,
to?: number = text.length
)
Sample usage at:
Replacing text between dollar signs for Mathml expression.
here is my code
function foo(){
}
after passing it through the default formatter(alt+shift+f) I get:
function foo() {
}
(note the added space in the first line)
My question is: how do I set up the formatter so it does not add the space?
I prefer my curly braces looking like this:
function eg()
{
}
But when I try to format my code, vscode auto corrects to this:
function eg() {
}
Is there any plugins that I can download or setting that I can tweak to change this?
Try :
"javascript.format.placeOpenBraceOnNewLineForFunctions": true;
"javascript.format.placeOpenBraceOnNewLineForControlBlocks": true;
"typescript.format.placeOpenBraceOnNewLineForControlBlocks": true;
"typescript.format.placeOpenBraceOnNewLineForFunctions": true;
In my part class I removed #Focus annotation method which implemented
#Focus
public void setFocus() {
viewer.getControl().setFocus();
}
after that tab text underline not visible. But when open window with single part tab text underline is visible, if I click anywhere on window underline gone.
How to remove tab text underline?
The underline is drawn if the CTabFolder used for the part has focus. So you should always define an #Focus method for the part and set the focus to some other control in the part.
The actual drawing of the tab is done by the tab renderer which you can set in the CSS using swt-tab-renderer:
CTabFolder
{
swt-tab-renderer: url('bundleclass://org.eclipse.e4.ui.workbench.renderers.swt/org.eclipse.e4.ui.workbench.renderers.swt.CTabRendering');
}
However tab renderers are rather complex and difficult to write.
The actual code in the standard renderer for the underline is:
if (parent.isFocusControl()) {
Display display = parent.getDisplay();
if (parent.simple || parent.single) {
gc.setBackground(display.getSystemColor(SWT.COLOR_BLACK));
gc.setForeground(display.getSystemColor(SWT.COLOR_WHITE));
gc.drawFocus(xDraw-1, textY-1, extent.x+2, extent.y+2);
} else {
gc.setForeground(display.getSystemColor(BUTTON_BORDER));
gc.drawLine(xDraw, textY+extent.y+1, xDraw+extent.x+1, textY+extent.y+1);
}
}
parent in this code is the CTabFolder (from org.eclipse.swt.custom.CTabFolderRenderer)
I'm trying to create a JAVA code formatter such that it doesn't wrap any lines. BUT for any lines in my code that I have manually wrapped I want the formatter to respect them and not format them in to one line.
For example:
public Class {
public Class(String a,
String b,
String c,
String d) {
// The constructor arguments should stay as they are
}
public void aMethod() {
// This statement should not be wrapped
get().doSomething().getAnohterMethodThatHasAReeeeeeeaalllyyLongName();
}
}
I have made the line width 9999 (the max), and I have turned off line wrapping for everything. What have I missed?
Thanks.
I opened the preference page for
"Java - Code Style - Formatter"
and activated "never join lines"
and selected "Do not wrap" in the combo box "line wrapping policy"
After this change i was able to write code, which was not wrapped.