com.google.gapid.widgets.MeasuringViewLabelProvider.java Source code

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Here is the source code for com.google.gapid.widgets.MeasuringViewLabelProvider.java

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/*
 * Copyright (C) 2017 Google Inc.
 *
 * 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.google.gapid.widgets;

import com.google.gapid.views.Formatter.LinkableStyledString;
import com.google.gapid.views.Formatter.StylingString;

import org.eclipse.jface.viewers.ColumnViewer;
import org.eclipse.jface.viewers.StyledCellLabelProvider;
import org.eclipse.jface.viewers.StyledString;
import org.eclipse.jface.viewers.ViewerCell;
import org.eclipse.swt.custom.StyleRange;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.TextLayout;
import org.eclipse.swt.widgets.Widget;

import java.util.Arrays;

/**
 * A {@link StyledCellLabelProvider} that can be used to measure the size of the label to correctly
 * determine if the the mouse pointer is hovering over a link in the {@link StylingString}.
 */
public abstract class MeasuringViewLabelProvider extends StyledCellLabelProvider {
    private final ColumnViewer viewer;
    private final Theme theme;
    private final TextLayout layout;

    public MeasuringViewLabelProvider(ColumnViewer viewer, Theme theme) {
        this.viewer = viewer;
        this.theme = theme;
        this.layout = new TextLayout(viewer.getControl().getDisplay());
    }

    @Override
    public void dispose() {
        super.dispose();
        layout.dispose();
    }

    @Override
    public void update(ViewerCell cell) {
        // Adjusted from the DelegatingStyledCellLabelProvider implementation.

        StyledString styledString = format(cell.getItem(), cell.getElement(), LinkableStyledString.ignoring(theme))
                .getString();
        String newText = styledString.toString();

        StyleRange[] oldStyleRanges = cell.getStyleRanges();
        StyleRange[] newStyleRanges = styledString.getStyleRanges();

        if (!Arrays.equals(oldStyleRanges, newStyleRanges)) {
            cell.setStyleRanges(newStyleRanges);
            if (cell.getText().equals(newText)) {
                cell.setText("");
            }
        }
        Color bgcolor = getBackgroundColor(cell.getElement());
        if (bgcolor != null) {
            cell.setBackground(bgcolor);
        }
        cell.setImage(getImage(cell.getElement()));
        cell.setText(newText);
    }

    protected Image getImage(@SuppressWarnings("unused") Object element) {
        return null;
    }

    protected Color getBackgroundColor(@SuppressWarnings("unused") Object element) {
        return null;
    }

    protected abstract <S extends StylingString> S format(Widget item, Object element, S string);

    public Object getFollow(Point point) {
        ViewerCell cell = viewer.getCell(point);
        if (cell == null || !isFollowable(cell.getElement())) {
            return null;
        }

        LinkableStyledString string = format(cell.getItem(), cell.getElement(), LinkableStyledString.create(theme));
        string.endLink();
        string.append("dummy", string.defaultStyle());
        updateLayout(cell, string.getString());

        Rectangle bounds = cell.getTextBounds();
        int offset = layout.getOffset(point.x - bounds.x, point.y - bounds.y, null);
        return string.getLinkTarget(offset);
    }

    protected abstract boolean isFollowable(Object element);

    private void updateLayout(ViewerCell cell, StyledString string) {
        // Adjusted from similar method from super class.
        layout.setStyle(null, 0, Integer.MAX_VALUE);
        layout.setText(string.toString());

        for (StyleRange range : cell.getStyleRanges()) {
            layout.setStyle(range, range.start, range.start + range.length - 1);
        }
    }
}