content: /*
   * Copyright (C) 2011 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.filterpacks.imageproc;
  
  import android.filterfw.core.Filter;
  import android.filterfw.core.FilterContext;
  import android.filterfw.core.Frame;
  import android.filterfw.core.FrameFormat;
  import android.filterfw.core.GenerateFieldPort;
  import android.filterfw.core.MutableFrameFormat;
  import android.filterfw.core.Program;
  import android.filterfw.core.ShaderProgram;
  import android.filterfw.format.ImageFormat;
  
  import java.lang.Math;
  /**
   * @hide
   */
  public class ToPackedGrayFilter extends Filter {
  
      @GenerateFieldPort(name = "owidth", hasDefault = true)
      private int mOWidth = FrameFormat.SIZE_UNSPECIFIED;
      @GenerateFieldPort(name = "oheight", hasDefault = true)
      private int mOHeight = FrameFormat.SIZE_UNSPECIFIED;
      @GenerateFieldPort(name = "keepAspectRatio", hasDefault = true)
      private boolean mKeepAspectRatio = false;
  
      private Program mProgram;
  
      private final String mColorToPackedGrayShader =
          "precision mediump float;\n" +
          "const vec4 coeff_y = vec4(0.299, 0.587, 0.114, 0);\n" +
          "uniform sampler2D tex_sampler_0;\n" +
          "uniform float pix_stride;\n" +
          "varying vec2 v_texcoord;\n" +
          "void main() {\n" +
          "  for (int i = 0; i < 4; ++i) {\n" +
          "    vec4 p = texture2D(tex_sampler_0,\n" +
          "                       v_texcoord + vec2(pix_stride * float(i), 0.0));\n" +
          "    gl_FragColor[i] = dot(p, coeff_y);\n" +
          "  }\n" +
          "}\n";
  
      public ToPackedGrayFilter(String name) {
          super(name);
      }
  
      @Override
      public void setupPorts() {
          addMaskedInputPort("image", ImageFormat.create(ImageFormat.COLORSPACE_RGBA,
                                                         FrameFormat.TARGET_GPU));
          addOutputBasedOnInput("image", "image");
      }
  
      @Override
      public FrameFormat getOutputFormat(String portName, FrameFormat inputFormat) {
          return convertInputFormat(inputFormat);
      }
  
      private void checkOutputDimensions(int outputWidth, int outputHeight) {
          if (outputWidth <= 0 || outputHeight <= 0) {
              throw new RuntimeException("Invalid output dimensions: " +
                                         outputWidth + " " + outputHeight);
          }
      }
  
      private FrameFormat convertInputFormat(FrameFormat inputFormat) {
          int ow = mOWidth;
          int oh = mOHeight;
          int w = inputFormat.getWidth();
          int h = inputFormat.getHeight();
          if (mOWidth == FrameFormat.SIZE_UNSPECIFIED) {
              ow = w;
          }
          if (mOHeight == FrameFormat.SIZE_UNSPECIFIED) {
              oh = h;
          }
          if (mKeepAspectRatio) {
              // if keep aspect ratio, use the bigger dimension to determine the
              // final output size
              if (w > h) {
                  ow = Math.max(ow, oh);
                  oh = ow * h / w;
              } else {
                  oh = Math.max(ow, oh);
                  ow = oh * w / h;
              }
          }
          ow = (ow > 0 && ow < 4) ? 4 : (ow / 4) * 4; // ensure width is multiple of 4
          return ImageFormat.create(ow, oh,
                                    ImageFormat.COLORSPACE_GRAY,
                                    FrameFormat.TARGET_NATIVE);
      }
  
      @Override
      public void prepare(FilterContext context) {
          mProgram = new ShaderProgram(context, mColorToPackedGrayShader);
      }
  
      @Override
      public void process(FilterContext context) {
          Frame input = pullInput("image");
          FrameFormat inputFormat = input.getFormat();
          FrameFormat outputFormat = convertInputFormat(inputFormat);
          int ow = outputFormat.getWidth();
          int oh = outputFormat.getHeight();
          checkOutputDimensions(ow, oh);
          mProgram.setHostValue("pix_stride", 1.0f / ow);
  
          // Do the RGBA to luminance conversion.
          MutableFrameFormat tempFrameFormat = inputFormat.mutableCopy();
          tempFrameFormat.setDimensions(ow / 4, oh);
          Frame temp = context.getFrameManager().newFrame(tempFrameFormat);
          mProgram.process(input, temp);
  
          // Read frame from GPU to CPU.
          Frame output = context.getFrameManager().newFrame(outputFormat);
          output.setDataFromFrame(temp);
          temp.release();
  
          // Push output and yield ownership.
          pushOutput("image", output);
          output.release();
      }
  
  }
  