diff options
Diffstat (limited to 'FrontEnd/src/components/ImageCropper.tsx')
| -rw-r--r-- | FrontEnd/src/components/ImageCropper.tsx | 312 |
1 files changed, 312 insertions, 0 deletions
diff --git a/FrontEnd/src/components/ImageCropper.tsx b/FrontEnd/src/components/ImageCropper.tsx new file mode 100644 index 00000000..f23994e2 --- /dev/null +++ b/FrontEnd/src/components/ImageCropper.tsx @@ -0,0 +1,312 @@ +import * as React from "react"; +import classnames from "classnames"; + +import { UiLogicError } from "~src/common"; + +import "./ImageCropper.css"; +import BlobImage from "./BlobImage"; + +export interface Clip { + left: number; + top: number; + width: number; +} + +interface NormailizedClip extends Clip { + height: number; +} + +interface ImageInfo { + width: number; + height: number; + landscape: boolean; + ratio: number; + maxClipWidth: number; + maxClipHeight: number; +} + +interface ImageCropperSavedState { + clip: NormailizedClip; + x: number; + y: number; + pointerId: number; +} + +export interface ImageCropperProps { + clip: Clip | null; + image: string | Blob; + onChange: (clip: Clip) => void; + imageElementCallback?: (element: HTMLImageElement | null) => void; + className?: string; +} + +const ImageCropper = (props: ImageCropperProps): React.ReactElement => { + const { clip, image, onChange, imageElementCallback, className } = props; + + const [oldState, setOldState] = React.useState<ImageCropperSavedState | null>( + null, + ); + const [imageInfo, setImageInfo] = React.useState<ImageInfo | null>(null); + + const normalizeClip = (c: Clip | null | undefined): NormailizedClip => { + if (c == null) { + return { left: 0, top: 0, width: 0, height: 0 }; + } + + return { + left: c.left || 0, + top: c.top || 0, + width: c.width || 0, + height: imageInfo != null ? (c.width || 0) / imageInfo.ratio : 0, + }; + }; + + const c = normalizeClip(clip); + + const imgElementRef = React.useRef<HTMLImageElement | null>(null); + + const onImageRef = React.useCallback( + (e: HTMLImageElement | null) => { + imgElementRef.current = e; + if (imageElementCallback != null && e == null) { + imageElementCallback(null); + } + }, + [imageElementCallback], + ); + + const onImageLoad = React.useCallback( + (e: React.SyntheticEvent<HTMLImageElement>) => { + const img = e.currentTarget; + const landscape = img.naturalWidth >= img.naturalHeight; + + const info = { + width: img.naturalWidth, + height: img.naturalHeight, + landscape, + ratio: img.naturalHeight / img.naturalWidth, + maxClipWidth: landscape ? img.naturalHeight / img.naturalWidth : 1, + maxClipHeight: landscape ? 1 : img.naturalWidth / img.naturalHeight, + }; + setImageInfo(info); + onChange({ left: 0, top: 0, width: info.maxClipWidth }); + if (imageElementCallback != null) { + imageElementCallback(img); + } + }, + [onChange, imageElementCallback], + ); + + const onPointerDown = React.useCallback( + (e: React.PointerEvent) => { + if (oldState != null) return; + e.currentTarget.setPointerCapture(e.pointerId); + setOldState({ + x: e.clientX, + y: e.clientY, + clip: c, + pointerId: e.pointerId, + }); + }, + [oldState, c], + ); + + const onPointerUp = React.useCallback( + (e: React.PointerEvent) => { + if (oldState == null || oldState.pointerId !== e.pointerId) return; + e.currentTarget.releasePointerCapture(e.pointerId); + setOldState(null); + }, + [oldState], + ); + + const onPointerMove = React.useCallback( + (e: React.PointerEvent) => { + if (oldState == null) return; + + const oldClip = oldState.clip; + + const movement = { x: e.clientX - oldState.x, y: e.clientY - oldState.y }; + + const { current: imgElement } = imgElementRef; + + if (imgElement == null) throw new UiLogicError("Image element is null."); + + const moveRatio = { + x: movement.x / imgElement.width, + y: movement.y / imgElement.height, + }; + + const newRatio = { + x: oldClip.left + moveRatio.x, + y: oldClip.top + moveRatio.y, + }; + if (newRatio.x < 0) { + newRatio.x = 0; + } else if (newRatio.x > 1 - oldClip.width) { + newRatio.x = 1 - oldClip.width; + } + if (newRatio.y < 0) { + newRatio.y = 0; + } else if (newRatio.y > 1 - oldClip.height) { + newRatio.y = 1 - oldClip.height; + } + + onChange({ left: newRatio.x, top: newRatio.y, width: oldClip.width }); + }, + [oldState, onChange], + ); + + const onHandlerPointerMove = React.useCallback( + (e: React.PointerEvent) => { + if (oldState == null) return; + + const oldClip = oldState.clip; + + const movement = { x: e.clientX - oldState.x, y: e.clientY - oldState.y }; + + const ratio = imageInfo == null ? 1 : imageInfo.ratio; + + const { current: imgElement } = imgElementRef; + + if (imgElement == null) throw new UiLogicError("Image element is null."); + + const moveRatio = { + x: movement.x / imgElement.width, + y: movement.x / imgElement.width / ratio, + }; + + const newRatio = { + x: oldClip.width + moveRatio.x, + y: oldClip.height + moveRatio.y, + }; + + const maxRatio = { + x: Math.min(1 - oldClip.left, newRatio.x), + y: Math.min(1 - oldClip.top, newRatio.y), + }; + + const maxWidthRatio = Math.min(maxRatio.x, maxRatio.y * ratio); + + let newWidth; + if (newRatio.x < 0) { + newWidth = 0; + } else if (newRatio.x > maxWidthRatio) { + newWidth = maxWidthRatio; + } else { + newWidth = newRatio.x; + } + + onChange({ left: oldClip.left, top: oldClip.top, width: newWidth }); + }, + [imageInfo, oldState, onChange], + ); + + const toPercentage = (n: number): string => `${n}%`; + + // fuck!!! I just can't find a better way to implement this in pure css + const containerStyle: React.CSSProperties = (() => { + if (imageInfo == null) { + return { width: "100%", paddingTop: "100%", height: 0 }; + } else { + if (imageInfo.ratio > 1) { + return { + width: toPercentage(100 / imageInfo.ratio), + paddingTop: "100%", + height: 0, + }; + } else { + return { + width: "100%", + paddingTop: toPercentage(100 * imageInfo.ratio), + height: 0, + }; + } + } + })(); + + return ( + <div + className={classnames("image-cropper-container", className)} + style={containerStyle} + > + <BlobImage + imgRef={onImageRef} + src={image} + onLoad={onImageLoad} + alt="to crop" + /> + <div className="image-cropper-mask-container"> + <div + className="image-cropper-mask" + style={{ + left: toPercentage(c.left * 100), + top: toPercentage(c.top * 100), + width: toPercentage(c.width * 100), + height: toPercentage(c.height * 100), + }} + onPointerMove={onPointerMove} + onPointerDown={onPointerDown} + onPointerUp={onPointerUp} + /> + </div> + <div + className="image-cropper-handler" + style={{ + left: `calc(${(c.left + c.width) * 100}% - 15px)`, + top: `calc(${(c.top + c.height) * 100}% - 15px)`, + }} + onPointerMove={onHandlerPointerMove} + onPointerDown={onPointerDown} + onPointerUp={onPointerUp} + /> + </div> + ); +}; + +export default ImageCropper; + +export function applyClipToImage( + image: HTMLImageElement, + clip: Clip, + mimeType: string, +): Promise<Blob> { + return new Promise((resolve, reject) => { + const naturalSize = { + width: image.naturalWidth, + height: image.naturalHeight, + }; + const clipArea = { + x: naturalSize.width * clip.left, + y: naturalSize.height * clip.top, + length: naturalSize.width * clip.width, + }; + + const canvas = document.createElement("canvas"); + canvas.width = clipArea.length; + canvas.height = clipArea.length; + const context = canvas.getContext("2d"); + + if (context == null) throw new Error("Failed to create context."); + + context.drawImage( + image, + clipArea.x, + clipArea.y, + clipArea.length, + clipArea.length, + 0, + 0, + clipArea.length, + clipArea.length, + ); + + canvas.toBlob((blob) => { + if (blob == null) { + reject(new Error("canvas.toBlob returns null")); + } else { + resolve(blob); + } + }, mimeType); + }); +} |