mirror of
https://github.com/vector-im/element-web.git
synced 2024-11-17 22:14:58 +08:00
344dac4fb9
We use `export default` begrudgingly here. Ideally we'd use just `export`, though this entire SDK expects things to be exported as a default. Instead of breaking everything, we'll sacrifice our export pattern for a smaller diff - a later commit can always do the default export -> regular export conversion.
54 lines
2.0 KiB
JavaScript
54 lines
2.0 KiB
JavaScript
/*
|
|
Copyright 2015, 2016 OpenMarket Ltd
|
|
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
|
you may not use this file except in compliance with the License.
|
|
You may obtain a copy of the License at
|
|
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
Unless required by applicable law or agreed to in writing, software
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
See the License for the specific language governing permissions and
|
|
limitations under the License.
|
|
*/
|
|
|
|
'use strict';
|
|
|
|
/**
|
|
* Returns the actual height that an image of dimensions (fullWidth, fullHeight)
|
|
* will occupy if resized to fit inside a thumbnail bounding box of size
|
|
* (thumbWidth, thumbHeight).
|
|
*
|
|
* If the aspect ratio of the source image is taller than the aspect ratio of
|
|
* the thumbnail bounding box, then we return the thumbHeight parameter unchanged.
|
|
* Otherwise we return the thumbHeight parameter scaled down appropriately to
|
|
* reflect the actual height the scaled thumbnail occupies.
|
|
*
|
|
* This is very useful for calculating how much height a thumbnail will actually
|
|
* consume in the timeline, when performing scroll offset calcuations
|
|
* (e.g. scroll locking)
|
|
*/
|
|
export function thumbHeight(fullWidth, fullHeight, thumbWidth, thumbHeight) {
|
|
if (!fullWidth || !fullHeight) {
|
|
// Cannot calculate thumbnail height for image: missing w/h in metadata. We can't even
|
|
// log this because it's spammy
|
|
return undefined;
|
|
}
|
|
if (fullWidth < thumbWidth && fullHeight < thumbHeight) {
|
|
// no scaling needs to be applied
|
|
return fullHeight;
|
|
}
|
|
const widthMulti = thumbWidth / fullWidth;
|
|
const heightMulti = thumbHeight / fullHeight;
|
|
if (widthMulti < heightMulti) {
|
|
// width is the dominant dimension so scaling will be fixed on that
|
|
return Math.floor(widthMulti * fullHeight);
|
|
} else {
|
|
// height is the dominant dimension so scaling will be fixed on that
|
|
return Math.floor(heightMulti * fullHeight);
|
|
}
|
|
}
|
|
|