79 lines
2.0 KiB
Java
79 lines
2.0 KiB
Java
package org.thoughtcrime.securesms.imageeditor;
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import android.graphics.Canvas;
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import android.graphics.Matrix;
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import android.graphics.RectF;
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import androidx.annotation.NonNull;
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/**
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* Tracks the current matrix for a canvas.
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* <p>
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* This is because you cannot reliably call {@link Canvas#setMatrix(Matrix)}.
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* {@link Canvas#getMatrix()} provides this hint in its documentation:
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* "track relevant transform state outside of the canvas."
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* <p>
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* To achieve this, any changes to the canvas matrix must be done via this class, including save and
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* restore operations where the matrix was altered in between.
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*/
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public final class CanvasMatrix {
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private final static int STACK_HEIGHT_LIMIT = 16;
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private final Canvas canvas;
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private final Matrix canvasMatrix = new Matrix();
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private final Matrix temp = new Matrix();
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private final Matrix[] stack = new Matrix[STACK_HEIGHT_LIMIT];
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private int stackHeight;
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CanvasMatrix(Canvas canvas) {
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this.canvas = canvas;
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for (int i = 0; i < stack.length; i++) {
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stack[i] = new Matrix();
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}
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}
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public void concat(@NonNull Matrix matrix) {
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canvas.concat(matrix);
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canvasMatrix.preConcat(matrix);
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}
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void save() {
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canvas.save();
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if (stackHeight == STACK_HEIGHT_LIMIT) {
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throw new AssertionError("Not enough space on stack");
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}
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stack[stackHeight++].set(canvasMatrix);
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}
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void restore() {
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canvas.restore();
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canvasMatrix.set(stack[--stackHeight]);
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}
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void getCurrent(@NonNull Matrix into) {
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into.set(canvasMatrix);
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}
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public void setToIdentity() {
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if (canvasMatrix.invert(temp)) {
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concat(temp);
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}
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}
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public void initial(Matrix viewMatrix) {
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concat(viewMatrix);
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}
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boolean mapRect(@NonNull RectF dst, @NonNull RectF src) {
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return canvasMatrix.mapRect(dst, src);
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}
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public void mapPoints(float[] dst, float[] src) {
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canvasMatrix.mapPoints(dst, src);
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}
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public void copyTo(@NonNull Matrix matrix) {
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matrix.set(canvasMatrix);
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}
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}
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