效果图如下：
一、为预览控件设置圆角
为控件设置ViewOutlineProvider
public RoundTextureView(Context context, AttributeSet attrs) {
super(context, attrs);
setOutlineProvider(new ViewOutlineProvider() {
@Override
public void getOutline(View view, Outline outline) {
Rect rect = new Rect(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
outline.setRoundRect(rect, radius);
}
});
setClipToOutline(true);
}
在需要时修改圆角值并更新
public void setRadius(int radius) {
this.radius = radius;
}
public void turnRound() {
invalidateOutline();
}
即可根据设置的圆角值更新控件显示的圆角大小。当控件为正方形，且圆角值为边长的一半，显示的就是圆形。
二、实现正方形预览
1. 设备支持1:1预览尺寸
首先介绍一种简单但是局限性较大的实现方式：将相机预览尺寸和预览控件的大小都调整为1:1。
一般Android设备都支持多种预览尺寸，以Samsung Tab S3为例
- 在使用Camera API时，其支持的预览尺寸如下：
2019-08-02 13:16:08.669 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPreviewSize: 1920x1080 2019-08-02 13:16:08.669 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPreviewSize: 1280x720 2019-08-02 13:16:08.669 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPreviewSize: 1440x1080 2019-08-02 13:16:08.669 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPreviewSize: 1088x1088 2019-08-02 13:16:08.670 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPreviewSize: 1056x864 2019-08-02 13:16:08.670 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPreviewSize: 960x720 2019-08-02 13:16:08.670 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPreviewSize: 720x480 2019-08-02 13:16:08.670 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPreviewSize: 640x480 2019-08-02 13:16:08.670 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPreviewSize: 352x288 2019-08-02 13:16:08.670 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPreviewSize: 320x240 2019-08-02 13:16:08.670 16407-16407/com.wsy.glcamerademo I/CameraHelper: supportedPreviewSize: 176x144
其中1:1的预览尺寸为：1088x1088。
- 在使用Camera2 API时，其支持的预览尺寸（其实也包含了PictureSize）如下：
2019-08-02 13:19:24.980 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 4128x3096 2019-08-02 13:19:24.980 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 4128x2322 2019-08-02 13:19:24.980 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 3264x2448 2019-08-02 13:19:24.980 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 3264x1836 2019-08-02 13:19:24.980 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 3024x3024 2019-08-02 13:19:24.980 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2976x2976 2019-08-02 13:19:24.980 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2880x2160 2019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2592x1944 2019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2560x1920 2019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2560x1440 2019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2560x1080 2019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2160x2160 2019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2048x1536 2019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 2048x1152 2019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 1936x1936 2019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 1920x1080 2019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 1440x1080 2019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 1280x960 2019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 1280x720 2019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 960x720 2019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 720x480 2019-08-02 13:19:24.981 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 640x480 2019-08-02 13:19:24.982 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 320x240 2019-08-02 13:19:24.982 16768-16768/com.wsy.glcamerademo I/Camera2Helper: getBestSupportedSize: 176x144
其中1:1的预览尺寸为：3024x3024、2976x2976、2160x2160、1936x1936。
只要我们选择1:1的预览尺寸，再将预览控件设置为正方形，即可实现正方形预览；
再通过设置预览控件的圆角为边长的一半，即可实现圆形预览。
2. 设备不支持1:1预览尺寸的情况
-
选择1:1预览尺寸的缺陷分析
-
分辨率局限性
上述说到，我们可以选择1:1的预览尺寸进行预览，但是局限性较高，
可选择范围都很小。如果相机不支持1:1的预览尺寸，这个方案就不可行了。 -
资源消耗
以Samsung tab S3为例，该设备使用Camera2 API时，支持的正方形预览尺寸都很大，在进行图像处理等操作时将占用较多系统资源。
-
分辨率局限性
-
处理不支持1:1预览尺寸的情况
- 添加一个1:1尺寸的ViewGroup
- 将TextureView放入ViewGroup
- 设置TextureView的margin值以达到显示中心正方形区域的效果
示意图
示例代码
//将预览控件和预览尺寸比例保持一致，避免拉伸
{
FrameLayout.LayoutParams textureViewLayoutParams = (FrameLayout.LayoutParams) textureView.getLayoutParams();
int newHeight = 0;
int newWidth = textureViewLayoutParams.width;
//横屏
if (displayOrientation % 180 == 0) {
newHeight = textureViewLayoutParams.width * previewSize.height / previewSize.width;
}
//竖屏
else {
newHeight = textureViewLayoutParams.width * previewSize.width / previewSize.height;
}
////当不是正方形预览的情况下，添加一层ViewGroup限制View的显示区域
if (newHeight != textureViewLayoutParams.height) {
insertFrameLayout = new RoundFrameLayout(CoverByParentCameraActivity.this);
int sideLength = Math.min(newWidth, newHeight);
FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams(sideLength, sideLength);
insertFrameLayout.setLayoutParams(layoutParams);
FrameLayout parentView = (FrameLayout) textureView.getParent();
parentView.removeView(textureView);
parentView.addView(insertFrameLayout);
insertFrameLayout.addView(textureView);
FrameLayout.LayoutParams newTextureViewLayoutParams = new FrameLayout.LayoutParams(newWidth, newHeight);
//横屏
if (displayOrientation % 180 == 0) {
newTextureViewLayoutParams.leftMargin = ((newHeight - newWidth) / 2);
}
//竖屏
else {
newTextureViewLayoutParams.topMargin = -(newHeight - newWidth) / 2;
}
textureView.setLayoutParams(newTextureViewLayoutParams);
}
}
三、使用GLSurfaceView进行自定义程度更高的预览
使用上面的方法操作已经可完成正方形和圆形预览，但是仅适用于原生相机，当我们的数据源并非是原生相机的情况时如何进行圆形预览？接下来介绍使用GLSurfaceView显示NV21的方案，完全是自己实现预览数据的绘制。
1. GLSurfaceView使用流程
OpenGL渲染YUV数据流程
其中的重点是渲染器（Renderer）的编写，Renderer的介绍如下：
/**
* A generic renderer interface.
* <p>
* The renderer is responsible for making OpenGL calls to render a frame.
* <p>
* GLSurfaceView clients typically create their own classes that implement
* this interface, and then call {@link GLSurfaceView#setRenderer} to
* register the renderer with the GLSurfaceView.
* <p>
*
* <div class="special reference">
* <h3>Developer Guides</h3>
* <p>For more information about how to use OpenGL, read the
* <a href="{@docRoot}guide/topics/graphics/opengl.html">OpenGL</a> developer guide.</p>
* </div>
*
* <h3>Threading</h3>
* The renderer will be called on a separate thread, so that rendering
* performance is decoupled from the UI thread. Clients typically need to
* communicate with the renderer from the UI thread, because that's where
* input events are received. Clients can communicate using any of the
* standard Java techniques for cross-thread communication, or they can
* use the {@link GLSurfaceView#queueEvent(Runnable)} convenience method.
* <p>
* <h3>EGL Context Lost</h3>
* There are situations where the EGL rendering context will be lost. This
* typically happens when device wakes up after going to sleep. When
* the EGL context is lost, all OpenGL resources (such as textures) that are
* associated with that context will be automatically deleted. In order to
* keep rendering correctly, a renderer must recreate any lost resources
* that it still needs. The {@link #onSurfaceCreated(GL10, EGLConfig)} method
* is a convenient place to do this.
*
*
* @see #setRenderer(Renderer)
*/
public interface Renderer {
/**
* Called when the surface is created or recreated.
* <p>
* Called when the rendering thread
* starts and whenever the EGL context is lost. The EGL context will typically
* be lost when the Android device awakes after going to sleep.
* <p>
* Since this method is called at the beginning of rendering, as well as
* every time the EGL context is lost, this method is a convenient place to put
* code to create resources that need to be created when the rendering
* starts, and that need to be recreated when the EGL context is lost.
* Textures are an example of a resource that you might want to create
* here.
* <p>
* Note that when the EGL context is lost, all OpenGL resources associated
* with that context will be automatically deleted. You do not need to call
* the corresponding "glDelete" methods such as glDeleteTextures to
* manually delete these lost resources.
* <p>
* @param gl the GL interface. Use <code>instanceof</code> to
* test if the interface supports GL11 or higher interfaces.
* @param config the EGLConfig of the created surface. Can be used
* to create matching pbuffers.
*/
void onSurfaceCreated(GL10 gl, EGLConfig config);
/**
* Called when the surface changed size.
* <p>
* Called after the surface is created and whenever
* the OpenGL ES surface size changes.
* <p>
* Typically you will set your viewport here. If your camera
* is fixed then you could also set your projection matrix here:
* <pre class="prettyprint">
* void onSurfaceChanged(GL10 gl, int width, int height) {
* gl.glViewport(0, 0, width, height);
* // for a fixed camera, set the projection too
* float ratio = (float) width / height;
* gl.glMatrixMode(GL10.GL_PROJECTION);
* gl.glLoadIdentity();
* gl.glFrustumf(-ratio, ratio, -1, 1, 1, 10);
* }
* </pre>
* @param gl the GL interface. Use <code>instanceof</code> to
* test if the interface supports GL11 or higher interfaces.
* @param width
* @param height
*/
void onSurfaceChanged(GL10 gl, int width, int height);
/**
* Called to draw the current frame.
* <p>
* This method is responsible for drawing the current frame.
* <p>
* The implementation of this method typically looks like this:
* <pre class="prettyprint">
* void onDrawFrame(GL10 gl) {
* gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
* //... other gl calls to render the scene ...
* }
* </pre>
* @param gl the GL interface. Use <code>instanceof</code> to
* test if the interface supports GL11 or higher interfaces.
*/
void onDrawFrame(GL10 gl);
}
-
void onSurfaceCreated(GL10 gl, EGLConfig config)
在Surface创建或重建的情况下回调 -
void onSurfaceChanged(GL10 gl, int width, int height)
在Surface的大小发生变化的情况下回调 -
void onDrawFrame(GL10 gl)
在这里实现绘制操作。当我们设置的renderMode为RENDERMODE_CONTINUOUSLY时，该函数将不断地执行；
当我们设置的renderMode为RENDERMODE_WHEN_DIRTY时，将只在创建完成和调用requestRender后才执行。一般我们选择RENDERMODE_WHEN_DIRTY渲染模式，避免过度绘制。
一般情况下，我们会自己实现一个Renderer，然后为GLSurfaceView设置Renderer，可以说，Renderer的编写是整个流程的核心步骤。以下是在void onSurfaceCreated(GL10 gl, EGLConfig config)进行的初始化操作和在void onDrawFrame(GL10 gl)进行的绘制操作的流程图：
渲染YUV数据的Renderer
2. 具体实现
- 坐标系介绍
- Android View坐标系 OpenGL世界坐标系
- 着色器编写
/**
* 顶点着色器
*/
private static String VERTEX_SHADER =
" attribute vec4 attr_position;
" +
" attribute vec2 attr_tc;
" +
" varying vec2 tc;
" +
" void main() {
" +
" gl_Position = attr_position;
" +
" tc = attr_tc;
" +
" }";
/**
* 片段着色器
*/
private static String FRAG_SHADER =
" varying vec2 tc;
" +
" uniform sampler2D ySampler;
" +
" uniform sampler2D uSampler;
" +
" uniform sampler2D vSampler;
" +
" const mat3 convertMat = mat3( 1.0, 1.0, 1.0, -0.001, -0.3441, 1.772, 1.402, -0.7141, -0.58060);
" +
" void main()
" +
" {
" +
" vec3 yuv;
" +
" yuv.x = texture2D(ySampler, tc).r;
" +
" yuv.y = texture2D(uSampler, tc).r - 0.5;
" +
" yuv.z = texture2D(vSampler, tc).r - 0.5;
" +
" gl_FragColor = vec4(convertMat * yuv, 1.0);
" +
" }";
-
内建变量解释
-
gl_Position
VERTEX_SHADER代码里的gl_Position代表绘制的空间坐标。由于我们是二维绘制，所以直接传入OpenGL二维坐标系的左下(-1,-1)、右下(1,-1)、左上(-1,1)、右上(1,1)，也就是{-1,-1,1,-1,-1,1,1,1} -
gl_FragColor
FRAG_SHADER代码里的gl_FragColor代表单个片元的颜色
-
-
其他变量解释
-
ySampler、uSampler、vSampler
分别代表Y、U、V纹理采样器 convertMat
根据以下公式：我们可得到一个YUV转RGB的矩阵R = Y + 1.402 (V - 128) G = Y - 0.34414 (U - 128) - 0.71414 (V - 128) B = Y + 1.772 (U - 128)
1.0, 1.0, 1.0, 0, -0.344, 1.77, 1.403, -0.714, 0
-
-
部分类型、函数的解释
-
vec3、vec4
分别代表三维向量、四维向量。 -
vec4 texture2D(sampler2D sampler, vec2 coord)
以指定的矩阵将采样器的图像纹理转换为颜色值；如：
texture2D(ySampler, tc).r获取到的是Y数据，
texture2D(uSampler, tc).r获取到的是U数据，
texture2D(vSampler, tc).r获取到的是V数据。
-
-
在Java代码中进行初始化
根据图像宽高创建Y、U、V对应的ByteBuffer纹理数据；
根据是否镜像显示、旋转角度选择对应的转换矩阵；public void init(boolean isMirror, int rotateDegree, int frameWidth, int frameHeight) { if (this.frameWidth == frameWidth && this.frameHeight == frameHeight && this.rotateDegree == rotateDegree && this.isMirror == isMirror) { return; } dataInput = false; this.frameWidth = frameWidth; this.frameHeight = frameHeight; this.rotateDegree = rotateDegree; this.isMirror = isMirror; yArray = new byte[this.frameWidth * this.frameHeight]; uArray = new byte[this.frameWidth * this.frameHeight / 4]; vArray = new byte[this.frameWidth * this.frameHeight / 4]; int yFrameSize = this.frameHeight * this.frameWidth; int uvFrameSize = yFrameSize >> 2; yBuf = ByteBuffer.allocateDirect(yFrameSize); yBuf.order(ByteOrder.nativeOrder()).position(0); uBuf = ByteBuffer.allocateDirect(uvFrameSize); uBuf.order(ByteOrder.nativeOrder()).position(0); vBuf = ByteBuffer.allocateDirect(uvFrameSize); vBuf.order(ByteOrder.nativeOrder()).position(0); // 顶点坐标 squareVertices = ByteBuffer .allocateDirect(GLUtil.SQUARE_VERTICES.length * FLOAT_SIZE_BYTES) .order(ByteOrder.nativeOrder()) .asFloatBuffer(); squareVertices.put(GLUtil.SQUARE_VERTICES).position(0); //纹理坐标 if (isMirror) { switch (rotateDegree) { case 0: coordVertice = GLUtil.MIRROR_COORD_VERTICES; break; case 90: coordVertice = GLUtil.ROTATE_90_MIRROR_COORD_VERTICES; break; case 180: coordVertice = GLUtil.ROTATE_180_MIRROR_COORD_VERTICES; break; case 270: coordVertice = GLUtil.ROTATE_270_MIRROR_COORD_VERTICES; break; default: break; } } else { switch (rotateDegree) { case 0: coordVertice = GLUtil.COORD_VERTICES; break; case 90: coordVertice = GLUtil.ROTATE_90_COORD_VERTICES; break; case 180: coordVertice = GLUtil.ROTATE_180_COORD_VERTICES; break; case 270: coordVertice = GLUtil.ROTATE_270_COORD_VERTICES; break; default: break; } } coordVertices = ByteBuffer.allocateDirect(coordVertice.length * FLOAT_SIZE_BYTES).order(ByteOrder.nativeOrder()).asFloatBuffer(); coordVertices.put(coordVertice).position(0); }在Surface创建完成时进行Renderer初始化
-
private void initRenderer() { rendererReady = false; createGLProgram(); //启用纹理 GLES20.glEnable(GLES20.GL_TEXTURE_2D); //创建纹理 createTexture(frameWidth, frameHeight, GLES20.GL_LUMINANCE, yTexture); createTexture(frameWidth / 2, frameHeight / 2, GLES20.GL_LUMINANCE, uTexture); createTexture(frameWidth / 2, frameHeight / 2, GLES20.GL_LUMINANCE, vTexture); rendererReady = true; }其中
createGLProgram用于创建OpenGL Program并关联着色器代码中的变量private void createGLProgram() { int programHandleMain = GLUtil.createShaderProgram(); if (programHandleMain != -1) { // 使用着色器程序 GLES20.glUseProgram(programHandleMain); // 获取顶点着色器变量 int glPosition = GLES20.glGetAttribLocation(programHandleMain, "attr_position"); int textureCoord = GLES20.glGetAttribLocation(programHandleMain, "attr_tc"); // 获取片段着色器变量 int ySampler = GLES20.glGetUniformLocation(programHandleMain, "ySampler"); int uSampler = GLES20.glGetUniformLocation(programHandleMain, "uSampler"); int vSampler = GLES20.glGetUniformLocation(programHandleMain, "vSampler"); //给变量赋值 /** * GLES20.GL_TEXTURE0 和 ySampler 绑定 * GLES20.GL_TEXTURE1 和 uSampler 绑定 * GLES20.GL_TEXTURE2 和 vSampler 绑定 * * 也就是说 glUniform1i的第二个参数代表图层序号 */ GLES20.glUniform1i(ySampler, 0); GLES20.glUniform1i(uSampler, 1); GLES20.glUniform1i(vSampler, 2); GLES20.glEnableVertexAttribArray(glPosition); GLES20.glEnableVertexAttribArray(textureCoord); /** * 设置Vertex Shader数据 */ squareVertices.position(0); GLES20.glVertexAttribPointer(glPosition, GLUtil.COUNT_PER_SQUARE_VERTICE, GLES20.GL_FLOAT, false, 8, squareVertices); coordVertices.position(0); GLES20.glVertexAttribPointer(textureCoord, GLUtil.COUNT_PER_COORD_VERTICES, GLES20.GL_FLOAT, false, 8, coordVertices); } }其中
createTexture用于根据宽高和格式创建纹理private void createTexture(int width, int height, int format, int[] textureId) { //创建纹理 GLES20.glGenTextures(1, textureId, 0); //绑定纹理 GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureId[0]); /** * {@link GLES20#GL_TEXTURE_WRAP_S}代表左右方向的纹理环绕模式 * {@link GLES20#GL_TEXTURE_WRAP_T}代表上下方向的纹理环绕模式 * * {@link GLES20#GL_REPEAT}：重复 * {@link GLES20#GL_MIRRORED_REPEAT}：镜像重复 * {@link GLES20#GL_CLAMP_TO_EDGE}：忽略边框截取 * * 例如我们使用{@link GLES20#GL_REPEAT}： * * squareVertices coordVertices * -1.0f, -1.0f, 1.0f, 1.0f, * 1.0f, -1.0f, 1.0f, 0.0f, -> 和textureView预览相同 * -1.0f, 1.0f, 0.0f, 1.0f, * 1.0f, 1.0f 0.0f, 0.0f * * squareVertices coordVertices * -1.0f, -1.0f, 2.0f, 2.0f, * 1.0f, -1.0f, 2.0f, 0.0f, -> 和textureView预览相比，分割成了4 块相同的预览（左下，右下，左上，右上） * -1.0f, 1.0f, 0.0f, 2.0f, * 1.0f, 1.0f 0.0f, 0.0f */ GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_REPEAT); GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_REPEAT); /** * {@link GLES20#GL_TEXTURE_MIN_FILTER}代表所显示的纹理比加载进来的纹理小时的情况 * {@link GLES20#GL_TEXTURE_MAG_FILTER}代表所显示的纹理比加载进来的纹理大时的情况 * * {@link GLES20#GL_NEAREST}：使用纹理中坐标最接近的一个像素的颜色作为需要绘制的像素颜色 * {@link GLES20#GL_LINEAR}：使用纹理中坐标最接近的若干个颜色，通过加权平均算法得到需要绘制的像素颜色 */ GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_NEAREST); GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR); GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, format, width, height, 0, format, GLES20.GL_UNSIGNED_BYTE, null); }- 在Java代码中调用绘制
在数据源获取到时裁剪并传入帧数据
@Override public void onPreview(final byte[] nv21, Camera camera) { //裁剪指定的图像区域 ImageUtil.cropNV21(nv21, this.squareNV21, previewSize.width, previewSize.height, cropRect); //刷新GLSurfaceView roundCameraGLSurfaceView.refreshFrameNV21(this.squareNV21); }NV21数据裁剪代码
/** * 裁剪NV21数据 * * @param originNV21 原始的NV21数据 * @param cropNV21 裁剪结果NV21数据，需要预先分配内存 * @param width 原始数据的宽度 * @param height 原始数据的高度 * @param left 原始数据被裁剪的区域的左边界 * @param top 原始数据被裁剪的区域的上边界 * @param right 原始数据被裁剪的区域的右边界 * @param bottom 原始数据被裁剪的区域的下边界 */ public static void cropNV21(byte[] originNV21, byte[] cropNV21, int width, int height, int left, int top, int right, int bottom) { int halfWidth = width / 2; int cropImageWidth = right - left; int cropImageHeight = bottom - top; //原数据Y左上 int originalYLineStart = top * width; int targetYIndex = 0; //原数据UV左上 int originalUVLineStart = width * height + top * halfWidth; //目标数据的UV起始值 int targetUVIndex = cropImageWidth * cropImageHeight; for (int i = top; i < bottom; i++) { System.arraycopy(originNV21, originalYLineStart + left, cropNV21, targetYIndex, cropImageWidth); originalYLineStart += width; targetYIndex += cropImageWidth; if ((i & 1) == 0) { System.arraycopy(originNV21, originalUVLineStart + left, cropNV21, targetUVIndex, cropImageWidth); originalUVLineStart += width; targetUVIndex += cropImageWidth; } } }传给GLSurafceView并刷新帧数据
/** * 传入NV21刷新帧 * * @param data NV21数据 */ public void refreshFrameNV21(byte[] data) { if (rendererReady) { yBuf.clear(); uBuf.clear(); vBuf.clear(); putNV21(data, frameWidth, frameHeight); dataInput = true; requestRender(); } }其中
putNV21用于将NV21中的Y、U、V数据分别取出/** * 将NV21数据的Y、U、V分量取出 * * @param src nv21帧数据 * @param width 宽度 * @param height 高度 */ private void putNV21(byte[] src, int width, int height) { int ySize = width * height; int frameSize = ySize * 3 / 2; //取分量y值 System.arraycopy(src, 0, yArray, 0, ySize); int k = 0; //取分量uv值 int index = ySize; while (index < frameSize) { vArray[k] = src[index++]; uArray[k++] = src[index++]; } yBuf.put(yArray).position(0); uBuf.put(uArray).position(0); vBuf.put(vArray).position(0); }在执行
requestRender后，onDrawFrame函数将被回调，在其中进行三个纹理的数据绑定并绘制@Override public void onDrawFrame(GL10 gl) { // 分别对每个纹理做激活、绑定、设置数据操作 if (dataInput) { //y GLES20.glActiveTexture(GLES20.GL_TEXTURE0); GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, yTexture[0]); GLES20.glTexSubImage2D(GLES20.GL_TEXTURE_2D, 0, 0, 0, frameWidth, frameHeight, GLES20.GL_LUMINANCE, GLES20.GL_UNSIGNED_BYTE, yBuf); //u GLES20.glActiveTexture(GLES20.GL_TEXTURE1); GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, uTexture[0]); GLES20.glTexSubImage2D(GLES20.GL_TEXTURE_2D, 0, 0, 0, frameWidth >> 1, frameHeight >> 1, GLES20.GL_LUMINANCE, GLES20.GL_UNSIGNED_BYTE, uBuf); //v GLES20.glActiveTexture(GLES20.GL_TEXTURE2); GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, vTexture[0]); GLES20.glTexSubImage2D(GLES20.GL_TEXTURE_2D, 0, 0, 0, frameWidth >> 1, frameHeight >> 1, GLES20.GL_LUMINANCE, GLES20.GL_UNSIGNED_BYTE, vBuf); //在数据绑定完成后进行绘制 GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4); } }即可完成绘制。
四、加一层边框
有时候需求并不仅仅是圆形预览这么简单，我们可能还要为相机预览加一层边框
边框效果
一样的思路，我们动态地修改边框值，并进行重绘。
边框自定义View中的相关代码如下：
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (paint == null) {
paint = new Paint();
paint.setStyle(Paint.Style.STROKE);
paint.setAntiAlias(true);
SweepGradient sweepGradient = new SweepGradient(((float) getWidth() / 2), ((float) getHeight() / 2),
new int[]{Color.GREEN, Color.CYAN, Color.BLUE, Color.CYAN, Color.GREEN}, null);
paint.setShader(sweepGradient);
}
drawBorder(canvas, 6);
}
private void drawBorder(Canvas canvas, int rectThickness) {
if (canvas == null) {
return;
}
paint.setStrokeWidth(rectThickness);
Path drawPath = new Path();
drawPath.addRoundRect(new RectF(0, 0, getWidth(), getHeight()), radius, radius, Path.Direction.CW);
canvas.drawPath(drawPath, paint);
}
public void turnRound() {
invalidate();
}
public void setRadius(int radius) {
this.radius = radius;
}
五、完整Demo代码：
https://github.com/wangshengyang1996/GLCameraDemo
- 使用Camera API和Camera2 API并选择最接近正方形的预览尺寸
- 使用Camera API并为其动态添加一层父控件，达到正方形预览的效果
- 使用Camera API获取预览数据，使用OpenGL的方式进行显示
https://ai.arcsoft.com.cn/ucenter/resource/openPlatform/index.html?cnblogs