I need to calculate the width
and the height
of the selected/highlighted text using JavaScript.
I am using the following code written by Tim Down, as the starting point,
function getSelectionCoords() {
var sel = document.selection, range;
var x = 0, y = 0;
if (sel) {
if (sel.type != "Control") {
range = sel.createRange();
range.collapse(true);
x = range.boundingLeft;
y = range.boundingTop;
}
} else if (window.getSelection) {
sel = window.getSelection();
if (sel.rangeCount) {
range = sel.getRangeAt(0).cloneRange();
if (range.getClientRects) {
range.collapse(true);
var rect = range.getClientRects()[0];
x = rect.left;
y = rect.top;
}
}
}
return { x: x, y: y };
}
The left
& the top
co-ordinates are being displayed correctly. To calculate the width & the height, I need the right
& the bottom
positions as well.
So I added few lines of code to find the bottom
& the right
positions (Code available here - http://jsfiddle.net/pankajparashar/kv2Bp/). But to my surprise, the code displays the left
& the right
co-ordinates always the same, even though there is visible difference between them (tested only in firefox).
There is no problem with the top
& the bottom
positions, as they are working perfectly, which will help me calculate the height. But to calculate the width, I would still need the correct right
co-ordinate.
Can anybody point any flaws with the code? or any alternate approach, using which I can calculate the width & the height of the selected text?
To calculate the length and width of a rectangle first, calculate the value of width 'w' by using the area of rectangle formula that is, 'w = A/l'. Then substitute the value of width in the formula of the perimeter of a rectangle and simplify the value of length 'l', that is, P = 2 (l + A/I).
Here's some code to get the dimensions of the selection's bounding rectangle. It's pretty similar to the original code.
Demo: http://jsfiddle.net/UFkjy/
function getSelectionDimensions() {
var sel = document.selection, range;
var width = 0, height = 0;
if (sel) {
if (sel.type != "Control") {
range = sel.createRange();
width = range.boundingWidth;
height = range.boundingHeight;
}
} else if (window.getSelection) {
sel = window.getSelection();
if (sel.rangeCount) {
range = sel.getRangeAt(0).cloneRange();
if (range.getBoundingClientRect) {
var rect = range.getBoundingClientRect();
width = rect.right - rect.left;
height = rect.bottom - rect.top;
}
}
}
return { width: width , height: height };
}
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