Make rectIntersection accept an array
#6311
Conversation
| export function rectIntersection(a, b) { | ||
| const x0 = Math.max(a.left, b.left); | ||
| const x1 = Math.min(a.left + a.width, b.left + b.width); | ||
| export function rectIntersection(layoutRects) { |
There was a problem hiding this comment.
Let's make this a variadic function, instead of passing an array:
rectIntersection(rect1, rect2, rect3, rect4);
function rectIntersection() {
// The "array" is `arguments`
for (var i = 0; i < arguments.length; i++) {
}
}There was a problem hiding this comment.
I like this. But what should I do with type check here?
There was a problem hiding this comment.
| const x1 = Math.min(a.left + a.width, b.left + b.width); | ||
| export function rectIntersection(layoutRects) { | ||
| const layoutRectArray = /** @type {Array<!LayoutRectDef>} */ | ||
| (layoutRects.filter(rect => { |
There was a problem hiding this comment.
Use continue in the for loop instead of iterating and allocating another array.
| } | ||
|
|
||
| current = layoutRectLtwh(x0, y0, x1 - x0, y1 - y0); |
There was a problem hiding this comment.
We can optimize this to only allocate 1 ever:
let x0 = first.left;
let x1 = x0 + first.width;
let y0 = first.top;
let y1 = y0 + first.height;
// Skip first
for (let i = 1; i < array.length; i++) {
// Do maths on x0, x1, y0, y1
// return null any time constraints are violated
}
return layoutRectLtwh(x0, y0, x1 - x0, y1 - y0);
zhouyx
force-pushed
the
rectIntersection
branch
from
dc1dc49
to
2d45c07
Compare
| elementRect = this.element_.getLayoutBox(); | ||
| dev().assert(elementRect.width >= 0 && elementRect.height >= 0, |
There was a problem hiding this comment.
This isn't necessary, not sure why we ever had it.
| let x1 = Infinity; | ||
| let y0 = -Infinity; | ||
| let y1 = Infinity; | ||
| let hasValidRect = false;; |
There was a problem hiding this comment.
Instead of this, just check if x1 is still Infinity.
| hasValidRect = true; | ||
| x0 = Math.max(x0, current.left); | ||
| x1 = Math.min(x1, current.left + current.width); | ||
| if (x1 < x0) { |
There was a problem hiding this comment.
Maybe combine this with the if below? Saving two Math calls won't really change much.
| @@ -244,8 +244,6 @@ export class IntersectionObserverPolyfill { | |||
| // If opt_iframe is not provided, all LayoutRect has position relative to | |||
| // the host document. | |||
| elementRect = this.element_.getLayoutBox(); | |||
| dev().assert(elementRect.width >= 0 && elementRect.height >= 0, | |||
There was a problem hiding this comment.
😄 Didn't delete because the other one we accept elementRect as an input. Has no control of the input. However since the only usecase now lives inside custom-element.js I think it's fine to delete at this time.
* git diff HEAD~1 * change intersection-observer cae * take multi arguments * remove console log * ... * minor * small change * remove another dev().assert
* git diff HEAD~1 * change intersection-observer cae * take multi arguments * remove console log * ... * minor * small change * remove another dev().assert
close #6288