design/designer-base/src/main/java/com/fr/design/cell/CellRectangleStylePreviewPane.java

package com.fr.design.cell;

import com.fr.base.CellBorderSourceFlag;
import com.fr.base.CellBorderStyle;
import com.fr.base.Style;
import com.fr.design.mainframe.theme.utils.DefaultThemedTemplateCellElementCase;
import com.fr.general.IOUtils;
import com.fr.report.cell.TemplateCellElement;

import javax.swing.JPanel;
import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Composite;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;

/**
 * @author Starryi
 * @version 1.0
 * Created by Starryi on 2021/9/3
 */
public class CellRectangleStylePreviewPane extends JPanel {

    private static final BufferedImage transparentBackgroundImage = IOUtils.readImage("/com/fr/design/images/transparent_background.png");
    private final float transparentBackgroundWidth;
    private final float transparentBackgroundHeight;

    private static final int ROW_COUNT = 2;
    private static final int COLUMN_COUNT = 2;

    private final TemplateCellElement[][] cellElementGrid = new TemplateCellElement[ROW_COUNT][COLUMN_COUNT];
    private final int[][] borderSourceFlags = new int[ROW_COUNT][COLUMN_COUNT];
    private final CellStylePreviewPane[][] cellStylePreviewPaneGrid = new CellStylePreviewPane[ROW_COUNT][COLUMN_COUNT];

    public CellRectangleStylePreviewPane(boolean supportInnerBorder) {
        transparentBackgroundWidth = transparentBackgroundImage.getWidth(null);
        transparentBackgroundHeight = transparentBackgroundImage.getHeight(null);

        setLayout(new GridLayout(2, 2));
        setOpaque(false);
        setBackground(null);

        for (int r = 0; r < ROW_COUNT; r++) {
            for (int c = 0; c < COLUMN_COUNT; c++) {
                CellStylePreviewPane pane = new CellStylePreviewPane(c, r, COLUMN_COUNT, ROW_COUNT, false, false);
                TemplateCellElement cellElement = DefaultThemedTemplateCellElementCase.createInstance(c, r);
                int flags = CellBorderSourceFlag.INVALID_BORDER_SOURCE;
                if (supportInnerBorder) {
                    flags = CellBorderSourceFlag.ALL_BORDER_SOURCE_OUTER;
                    if (r != 0) {
                        flags |= CellBorderSourceFlag.TOP_BORDER_SOURCE_INNER;
                    }
                    if (r != ROW_COUNT - 1) {
                        flags |= CellBorderSourceFlag.BOTTOM_BORDER_SOURCE_INNER;
                    }
                    if (c != 0) {
                        flags |= CellBorderSourceFlag.LEFT_BORDER_SOURCE_INNER;
                    }
                    if (c != COLUMN_COUNT - 1) {
                        flags |= CellBorderSourceFlag.RIGHT_BORDER_SOURCE_INNER;
                    }
                }


                pane.setStyle(cellElement.getStyle());
                add(pane);

                cellElementGrid[r][c] = cellElement;
                borderSourceFlags[r][c] = flags;
                cellStylePreviewPaneGrid[r][c] = pane;
            }
        }
    }

    public void setPlainText(String text) {
        cellStylePreviewPaneGrid[0][1].setPaintText(text);
        cellStylePreviewPaneGrid[1][1].setPaintText(text);
        repaint();
    }

    public void setStyle(Style style, CellBorderStyle borderStyle) {
        for (int i = 0; i < ROW_COUNT; i++) {
            for (int j = 0; j < COLUMN_COUNT; j++) {
                CellStylePreviewPane pane = cellStylePreviewPaneGrid[i][j];
                TemplateCellElement cellElement = cellElementGrid[i][j];
                int flag = borderSourceFlags[i][j];
                cellElement.setStyle(CellBorderSourceFlag.deriveBorderedStyle(style, borderStyle, flag));

                pane.setStyle(cellElement.getStyle());
            }
        }
        repaint();
    }

    @Override
    public void setPreferredSize(Dimension preferredSize) {
        super.setPreferredSize(preferredSize);
        int hw = preferredSize.width / 2;
        int hh = preferredSize.height / 2;
        cellStylePreviewPaneGrid[0][0].setPreferredSize(new Dimension(hw, hh));
        cellStylePreviewPaneGrid[0][1].setPreferredSize(new Dimension(hw, hh));
        cellStylePreviewPaneGrid[1][0].setPreferredSize(new Dimension(hw, hh));
        cellStylePreviewPaneGrid[1][1].setPreferredSize(new Dimension(hw, hh));
    }

    @Override
    public Dimension getPreferredSize() {
        Dimension d00 = cellStylePreviewPaneGrid[0][0].getPreferredSize();
        Dimension d01 = cellStylePreviewPaneGrid[0][1].getPreferredSize();
        Dimension d10 = cellStylePreviewPaneGrid[1][0].getPreferredSize();
        Dimension d11 = cellStylePreviewPaneGrid[1][1].getPreferredSize();

        int width = Math.max(d00.width + d01.width, d10.width + d11.width);
        int height = Math.max(d00.height + d10.height, d01.height + d11.height);

        return new Dimension(width, height);
    }

    @Override
    public void paint(Graphics g) {
        Graphics2D g2d = (Graphics2D) g;
        g2d.clearRect(0, 0, getWidth(), getHeight());

        g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        g2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);

        paintTransparentBackground((Graphics2D) g, cellElementGrid[0][0].getStyle());

        g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_OFF);
        g2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_OFF);

        super.paint(g);
    }

    @Override
    public Rectangle getBounds() {
        return super.getBounds();
    }

    private void paintTransparentBackground(Graphics2D g2d, Style style) {
        float alpha = computeTransparentBackgroundAlpha(style);

        float scaleWidth = 1.0F * getWidth() / transparentBackgroundWidth;
        float scaleHeight = 1.0F * getHeight() / transparentBackgroundHeight;
        float maxScale = Math.max(scaleWidth, scaleHeight);

        if (maxScale <= 1) {
            scaleWidth = scaleHeight = 1;
        } else {
            scaleHeight = scaleWidth = maxScale;
        }

        Composite oldComposite = g2d.getComposite();
        g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, alpha));
        g2d.drawImage(transparentBackgroundImage, 0, 0, (int) (transparentBackgroundWidth * scaleWidth), (int) (transparentBackgroundHeight * scaleHeight), null);
        g2d.setComposite(oldComposite);
    }

    private float computeTextColorBrightness(Style style) {
        Color fontColor = style.getFRFont().getForeground();
        return fontColor.getRed() * 0.299F + fontColor.getGreen() * 0.587F + fontColor.getBlue() * 0.114F;
    }

    private float computeTransparentBackgroundAlpha(Style style) {
        float textBrightness = computeTextColorBrightness(style);

        float alpha = 1.0F;
        if (textBrightness < 50) {
            alpha = 0.2F;
        } else if (textBrightness < 160){
            alpha = 0.5F;
        }
        return alpha;
    }
}