REPORT-59674 FR11新主题，单元格样式跟随主题时，样式选择中的字体看不清

【问题原因】
修改单元格样式阅览面板中透明图片的透明度规则，根据文字颜色
自动调整图片透明度

【改动思路】
同上

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

@@ -6,6 +6,9 @@ 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;
@@ -40,10 +43,21 @@ public class CellStylePreviewPane extends JPanel {
     @Override
     public void paint(Graphics g) {
         Graphics2D g2d = (Graphics2D) g;
-        int resolution = ScreenResolution.getScreenResolution();
 
-        int width = getWidth();
-        int height = getHeight();
+        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;
@@ -54,7 +68,18 @@ public class CellStylePreviewPane extends JPanel {
         } 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