Camera.java

/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * 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.
 */

package android.graphics;

/**
 * A camera instance can be used to compute 3D transformations and
 * generate a matrix that can be applied, for instance, on a
 * {@link Canvas}.
 */
public class Camera {
    private Matrix mMatrix;

    /**
     * Creates a new camera, with empty transformations.
     */
    public Camera() {
        nativeConstructor();
    }

    /**
     * Saves the camera state. Each save should be balanced
     * with a call to {@link #restore()}.
     * 
     * @see #save() 
     */
    public native void save();

    /**
     * Restores the saved state, if any.
     * 
     * @see #restore() 
     */
    public native void restore();

    /**
     * Applies a translation transform on all three axis.
     * 
     * @param x The distance to translate by on the X axis
     * @param y The distance to translate by on the Y axis
     * @param z The distance to translate by on the Z axis
     */
    public native void translate(float x, float y, float z);

    /**
     * Applies a rotation transform around the X axis.
     * 
     * @param deg The angle of rotation around the X axis, in degrees
     * 
     * @see #rotateY(float)
     * @see #rotateZ(float)
     * @see #rotate(float, float, float)
     */
    public native void rotateX(float deg);

    /**
     * Applies a rotation transform around the Y axis.
     * 
     * @param deg The angle of rotation around the Y axis, in degrees
     * 
     * @see #rotateX(float)
     * @see #rotateZ(float)
     * @see #rotate(float, float, float) 
     */
    public native void rotateY(float deg);

    /**
     * Applies a rotation transform around the Z axis.
     * 
     * @param deg The angle of rotation around the Z axis, in degrees
     * 
     * @see #rotateX(float)
     * @see #rotateY(float)
     * @see #rotate(float, float, float)
     */    
    public native void rotateZ(float deg);

    /**
     * Applies a rotation transform around all three axis.
     * 
     * @param x The angle of rotation around the X axis, in degrees
     * @param y The angle of rotation around the Y axis, in degrees
     * @param z The angle of rotation around the Z axis, in degrees
     * 
     * @see #rotateX(float)
     * @see #rotateY(float)
     * @see #rotateZ(float)
     */
    public native void rotate(float x, float y, float z);

    /**
     * Gets the x location of the camera.
     *
     * @see #setLocation(float, float, float)
     */
    public native float getLocationX();

    /**
     * Gets the y location of the camera.
     *
     * @see #setLocation(float, float, float)
     */
    public native float getLocationY();

    /**
     * Gets the z location of the camera.
     *
     * @see #setLocation(float, float, float)
     */
    public native float getLocationZ();

    /**
     * Sets the location of the camera. The default location is set at
     * 0, 0, -8.
     * 
     * @param x The x location of the camera
     * @param y The y location of the camera
     * @param z The z location of the camera
     */
    public native void setLocation(float x, float y, float z);

    /**
     * Computes the matrix corresponding to the current transformation
     * and copies it to the supplied matrix object.
     * 
     * @param matrix The matrix to copy the current transforms into
     */
    public void getMatrix(Matrix matrix) {
        nativeGetMatrix(matrix.native_instance);
    }

    /**
     * Computes the matrix corresponding to the current transformation
     * and applies it to the specified Canvas.
     * 
     * @param canvas The Canvas to set the transform matrix onto
     */
    public void applyToCanvas(Canvas canvas) {
        if (canvas.isHardwareAccelerated()) {
            if (mMatrix == null) mMatrix = new Matrix();
            getMatrix(mMatrix);
            canvas.concat(mMatrix);
        } else {
            nativeApplyToCanvas(canvas.getNativeCanvasWrapper());
        }
    }

    public native float dotWithNormal(float dx, float dy, float dz);

    protected void finalize() throws Throwable {
        try {
            nativeDestructor();
        } finally {
            super.finalize();
        }
    }

    private native void nativeConstructor();
    private native void nativeDestructor();
    private native void nativeGetMatrix(long native_matrix);
    private native void nativeApplyToCanvas(long native_canvas);

    long native_instance;
}