android/src/com/intellij/android/designer/designSurface/layout/FrameLayoutOperation.java

/*
 * Copyright 2000-2012 JetBrains s.r.o.
 *
 * 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 com.intellij.android.designer.designSurface.layout;

import com.android.SdkConstants;
import com.intellij.android.designer.designSurface.AbstractEditOperation;
import com.intellij.android.designer.designSurface.feedbacks.TextFeedback;
import com.intellij.android.designer.designSurface.graphics.DesignerGraphics;
import com.intellij.android.designer.designSurface.graphics.DrawingStyle;
import com.intellij.android.designer.model.RadViewComponent;
import com.intellij.android.designer.model.layout.Gravity;
import com.intellij.designer.designSurface.FeedbackLayer;
import com.intellij.designer.designSurface.OperationContext;
import com.intellij.designer.model.RadComponent;
import com.intellij.openapi.application.ApplicationManager;
import com.intellij.openapi.util.Pair;
import com.intellij.ui.IdeBorderFactory;
import com.intellij.util.containers.hash.HashSet;
import org.jetbrains.annotations.Nullable;

import javax.swing.*;
import java.awt.*;
import java.util.Collections;
import java.util.Set;

/**
 * @author Alexander Lobas
 */
public class FrameLayoutOperation extends AbstractEditOperation {
  private Set<Pair<Gravity, Gravity>> myExcludes = Collections.emptySet();
  private GravityFeedback myFeedback;
  private TextFeedback myTextFeedback;
  private Rectangle myBounds;
  private String myGravity;

  public FrameLayoutOperation(RadComponent container, OperationContext context) {
    super(container, context);

    if (context.isMove()) {
      myExcludes = new HashSet<Pair<Gravity, Gravity>>();

      for (RadComponent component : context.getComponents()) {
        myExcludes.add(Gravity.getSides(component));
      }
    }
  }

  private void createFeedback() {
    if (myFeedback == null) {
      FeedbackLayer layer = myContext.getArea().getFeedbackLayer();
      myBounds = ((RadViewComponent)myContainer).getPaddedBounds(layer);

      myFeedback = new GravityFeedback();
      myFeedback.setBounds(myBounds);
      layer.add(myFeedback);

      myTextFeedback = new TextFeedback();
      myTextFeedback.setBorder(IdeBorderFactory.createEmptyBorder(0, 3, 2, 0));
      layer.add(myTextFeedback);

      layer.repaint();
    }
  }

  @Override
  public void showFeedback() {
    createFeedback();

    Point location = myContext.getLocation();
    Gravity horizontal = calculateHorizontal(myBounds, location);
    Gravity vertical = calculateVertical(myBounds, location);

    if (myContext.isMove() && exclude(horizontal, vertical)) {
      horizontal = vertical = null;
    }

    myFeedback.setGravity(horizontal, vertical);
    configureTextFeedback(myBounds, horizontal, vertical);

    myGravity = Gravity.getValue(horizontal, vertical);
  }

  private void configureTextFeedback(Rectangle bounds, @Nullable Gravity horizontal, @Nullable Gravity vertical) {
    myTextFeedback.clear();

    if (horizontal == null || vertical == null) {
      myTextFeedback.bold("None");
    }
    else {
      myTextFeedback.bold("[" + vertical.name() + ", " + horizontal.name() + "]");
    }

    myTextFeedback.centerTop(bounds);
  }

  @Override
  public void eraseFeedback() {
    if (myFeedback != null) {
      FeedbackLayer layer = myContext.getArea().getFeedbackLayer();
      layer.remove(myFeedback);
      layer.remove(myTextFeedback);
      layer.repaint();
      myFeedback = null;
      myTextFeedback = null;
    }
  }

  @Nullable
  private static Gravity calculateHorizontal(Rectangle bounds, Point location) {
    if (bounds.width < 10) {
      return Gravity.left;
    }

    Gravity horizontal = null;
    double left = bounds.x + bounds.width / 3.0;
    double right = bounds.x + 2 * bounds.width / 3.0;

    if (location.x < left) {
      horizontal = Gravity.left;
    }
    else if (left < location.x && location.x < right) {
      horizontal = Gravity.center;
    }
    else if (location.x > right) {
      horizontal = Gravity.right;
    }

    return horizontal;
  }

  @Nullable
  private static Gravity calculateVertical(Rectangle bounds, Point location) {
    if (bounds.height < 10) {
      return Gravity.top;
    }

    Gravity vertical = null;
    double top = bounds.y + bounds.height / 3.0;
    double bottom = bounds.y + 2 * bounds.height / 3.0;

    if (location.y < top) {
      vertical = Gravity.top;
    }
    else if (top < location.y && location.y < bottom) {
      vertical = Gravity.center;
    }
    else if (location.y > bottom) {
      vertical = Gravity.bottom;
    }

    return vertical;
  }

  private boolean exclude(@Nullable Gravity horizontal, @Nullable Gravity vertical) {
    for (Pair<Gravity, Gravity> p : myExcludes) {
      if (p.first == horizontal && p.second == vertical) {
        return true;
      }
    }

    return false;
  }

  @Override
  public boolean canExecute() {
    return myGravity != null;
  }

  @Override
  public void execute() throws Exception {
    super.execute();

    ApplicationManager.getApplication().runWriteAction(new Runnable() {
      @Override
      public void run() {
        for (RadComponent component : myComponents) {
          ((RadViewComponent)component).getTag().setAttribute("layout_gravity", SdkConstants.NS_RESOURCES, myGravity);
        }
      }
    });
  }

  //////////////////////////////////////////////////////////////////////////////////////////
  //
  // Feedback
  //
  //////////////////////////////////////////////////////////////////////////////////////////

  private static final Gravity[] HORIZONTALS = {Gravity.left, Gravity.center, Gravity.right};
  private static final Gravity[] VERTICALS = {Gravity.top, Gravity.center, Gravity.bottom};

  private class GravityFeedback extends JComponent {
    @Nullable private Gravity myHorizontal;
    @Nullable private Gravity myVertical;

    public GravityFeedback() {
    }

    public void setGravity(@Nullable Gravity horizontal, @Nullable Gravity vertical) {
      myHorizontal = horizontal;
      myVertical = vertical;
      repaint();
    }

    @Override
    protected void paintComponent(Graphics g) {
      super.paintComponent(g);

      Rectangle bounds = ((RadViewComponent)myContainer).getPaddedBounds(this);
      DesignerGraphics.drawRect(DrawingStyle.DROP_PREVIEW, g, bounds.x, bounds.y, bounds.width, bounds.height);

      for (Gravity h : HORIZONTALS) {
        for (Gravity v : VERTICALS) {
          boolean selection = (myHorizontal == h && myVertical == v);
          if (selection || !exclude(h, v)) {
            paintCell(g, h, v, selection);
          }
        }
      }
    }

    private boolean paintCell(Graphics g, Gravity horizontal, Gravity vertical, boolean selection) {
      int x = 0;
      int width = (getWidth() - 2) / 3;
      if (horizontal == Gravity.center) {
        x = width + 1;
      }
      else if (horizontal == Gravity.right) {
        x = getWidth() - width;
      }

      int y = 0;
      int height = (getHeight() - 2) / 3;
      if (vertical == Gravity.center) {
        y = height + 1;
      }
      else if (vertical == Gravity.bottom) {
        y = getHeight() - height;
      }

      int hSpace = Math.min(5, Math.max(1, getWidth() / 30));
      if (hSpace > 1) {
        x += hSpace;
        width -= 2 * hSpace;
      }

      int vSpace = Math.min(5, Math.max(1, getHeight() / 30));
      if (vSpace > 1) {
        y += vSpace;
        height -= 2 * vSpace;
      }

      if (selection) {
        if (myHorizontal == horizontal && myVertical == vertical) {
          DesignerGraphics.drawFilledRect(DrawingStyle.DROP_ZONE_ACTIVE, g, x, y, width, height);

          return true;
        }
      }
      else {
        DesignerGraphics.drawFilledRect(DrawingStyle.DROP_ZONE, g, x, y, width, height);
      }

      return false;
    }
  }
}