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

package com.fr.design.cell;

import com.fr.base.NameStyle;
import com.fr.base.ScreenResolution;
import com.fr.base.Style;
import com.fr.general.IOUtils;

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.image.BufferedImage;

/**
 * @author Starryi
 * @version 1.0
 * Created by Starryi on 2021/9/3
 */
public class CellStylePreviewPane 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 String paintText = "Report";
    private Style style = Style.DEFAULT_STYLE;

    public CellStylePreviewPane() {
        transparentBackgroundWidth = transparentBackgroundImage.getWidth(null);
        transparentBackgroundHeight = transparentBackgroundImage.getHeight(null);
    }

    public void setStyle(Style style) {
        this.style = style;
        if (style instanceof NameStyle) {
            paintText = ((NameStyle) style).getName();
        }
        repaint();
    }

    @Override
    public void paint(Graphics g) {
        Graphics2D g2d = (Graphics2D) g;

        paintTransparentBackground(g2d, style);

        paintCellStyle(g2d, style);
    }

    private void paintTransparentBackground(Graphics2D g2d, Style style) {
        Color fontColor = style.getFRFont().getForeground();
        float g = fontColor.getRed() * 0.299F + fontColor.getGreen() * 0.587F * fontColor.getBlue() * 0.114F;
        float alpha = 1.0F;
        if (g < 50) {
            alpha = 0.2F;
        } else if (g < 160){
            alpha = 0.5F;
        }

        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 void paintCellStyle(Graphics2D g2d, Style style) {
        int resolution = ScreenResolution.getScreenResolution();

        int width = getWidth();
        int height = getHeight();

        if (style == Style.DEFAULT_STYLE) {
            // 如果是默认的style,就只写"Report"上去
            Style.paintContent(g2d, paintText, style, width, height, resolution);
            return;
        }

        Style.paintBackground(g2d, style, width, height);

        Style.paintContent(g2d, paintText, style, width, height, resolution);

        Style.paintBorder(g2d, style, width, height);
    }

    @Override
    public Dimension getMinimumSize() {
        return getPreferredSize();
    }
}