gatsby-plugin-utils
Version:
Gatsby utils that help creating plugins
79 lines (76 loc) • 2.79 kB
JavaScript
;
exports.__esModule = true;
exports.calculateImageDimensions = calculateImageDimensions;
exports.validateAndNormalizeFormats = validateAndNormalizeFormats;
function validateAndNormalizeFormats(formats, sourceFormat) {
const formatSet = new Set(formats);
// convert auto in format of source image
if (formatSet.has(`auto`)) {
formatSet.delete(`auto`);
formatSet.add(sourceFormat);
}
if (formatSet.has(`jpg`) && formatSet.has(`png`)) {
throw new Error(`Cannot specify both JPG and PNG formats`);
}
return formatSet;
}
/**
* Generate correct width and height like sharp will do
* @see https://sharp.pixelplumbing.com/api-resize#resize
*/
function calculateImageDimensions(originalDimensions, {
fit,
width: requestedWidth,
height: requestedHeight,
aspectRatio: requestedAspectRatio
}) {
// Calculate the eventual width/height of the image.
let imageAspectRatio;
if (requestedAspectRatio) {
imageAspectRatio = requestedAspectRatio;
} else {
imageAspectRatio = originalDimensions.width / originalDimensions.height;
}
let width = requestedWidth;
let height = requestedHeight;
switch (fit) {
case `inside`:
{
const widthOption = requestedWidth !== null && requestedWidth !== void 0 ? requestedWidth : Number.MAX_SAFE_INTEGER;
const heightOption = requestedHeight !== null && requestedHeight !== void 0 ? requestedHeight : Number.MAX_SAFE_INTEGER;
width = Math.min(widthOption, Math.round(heightOption * imageAspectRatio));
height = Math.min(heightOption, Math.round(widthOption / imageAspectRatio));
break;
}
case `outside`:
{
const widthOption = requestedWidth !== null && requestedWidth !== void 0 ? requestedWidth : 0;
const heightOption = requestedHeight !== null && requestedHeight !== void 0 ? requestedHeight : 0;
width = Math.max(widthOption, Math.round(heightOption * imageAspectRatio));
height = Math.max(heightOption, Math.round(widthOption / imageAspectRatio));
break;
}
case `fill`:
{
width = requestedWidth !== null && requestedWidth !== void 0 ? requestedWidth : originalDimensions.width;
height = requestedHeight !== null && requestedHeight !== void 0 ? requestedHeight : originalDimensions.height;
break;
}
default:
{
if (requestedWidth && !requestedHeight) {
width = requestedWidth;
height = Math.round(requestedWidth / imageAspectRatio);
}
if (requestedHeight && !requestedWidth) {
width = Math.round(requestedHeight * imageAspectRatio);
height = requestedHeight;
}
}
}
return {
width: width,
height: height,
aspectRatio: width / height
};
}