REPORT-53175 【10.0.18】组件背景分离为标题/背景/边框

优化样式面板中线型选择下拉列表的显示，原有的渲染方法会导致
显示文字"无"时字体过大（使用了默认字体），超出下拉框的高度从而
被截断，且不支持其他文字选项.

优化后的文字渲染逻辑使用默认的JComboBox的文字渲染方法，即通过
JComboBox内部的JLabel控件渲染文字. 且提供toStringFromStyle
接口方法，将对应的Int类型线型值，转变为可渲染的文本.

designer-base/src/main/java/com/fr/design/gui/icombobox/LineComboBox.java

@@ -3,22 +3,14 @@
  */
 package com.fr.design.gui.icombobox;
 
-import com.fr.base.FRContext;
 import com.fr.base.GraphHelper;
-import com.fr.base.ScreenResolution;
-import com.fr.general.FRFont;
 import com.fr.stable.Constants;
-import java.awt.Component;
+import com.fr.stable.StringUtils;
-import java.awt.Dimension;
+
-import java.awt.Font;
+import javax.swing.*;
-import java.awt.FontMetrics;
+import java.awt.*;
-import java.awt.Graphics;
-import java.awt.Graphics2D;
 import java.awt.geom.GeneralPath;
 import java.awt.geom.Point2D;
-import javax.swing.DefaultComboBoxModel;
-import javax.swing.JLabel;
-import javax.swing.JList;
 
 
 /**
@@ -59,6 +51,13 @@ public class LineComboBox extends UIComboBox {
     	this.setSelectedItem(new Integer(style));
     }
 
+    protected String toStringFromStyle(int style) {
+        if (style == Constants.LINE_NONE) {
+            return com.fr.design.i18n.Toolkit.i18nText("Fine-Design_Report_None");
+        }
+        return null;
+    }
+
     /**
      * CellRenderer.
      */
@@ -67,33 +66,29 @@ public class LineComboBox extends UIComboBox {
                 JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
         	JLabel comp= (JLabel)super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
             this.style = ((Integer) value).intValue();
+            String displayString = toStringFromStyle(style);
+            if (StringUtils.isNotEmpty(displayString)) {
+                comp.setText(" " + displayString);
+            } else {
                 comp.setText(null);
+            }
             return comp;
         }
 
         public void paint(Graphics g) {
         	super.paint(g);
+        	if (StringUtils.isEmpty(toStringFromStyle(style))) {
                 Graphics2D g2d = (Graphics2D) g;
 
                 Dimension d = getSize();
                 g2d.setColor(getForeground());
-            
-            FRFont font = FRContext.getDefaultValues().getFRFont();
-            int resolution = ScreenResolution.getScreenResolution();
-            Font rfont = font.applyResolutionNP(resolution);
-            g2d.setFont(rfont);
-            FontMetrics fm = GraphHelper.getFontMetrics(rfont);
-            if (style == Constants.LINE_NONE) {
-                //draw "none" string
-                GraphHelper.drawString(g2d, com.fr.design.i18n.Toolkit.i18nText("Fine-Design_Report_None"), 4, (d.height - fm.getHeight()) / 2D + fm.getAscent());
-            } else {
                 GraphHelper.drawLine(g2d, 4, d.height / 2D, d.width - 8D, d.height / 2D, style);
-            }
 
                 if(isShowAxisWithLineStyle()) { //  带有坐标轴箭头的样式.
                     drawArrow(g2d, new Point2D.Double(4, d.height / 2D), new Point2D.Double(d.width - 8D, d.height / 2D));
                 }
             }
+        }
         
         private void drawArrow(Graphics2D g2d, Point2D p0, Point2D p1) {
         	Point2D s = new Point2D.Double(p1.getX() - p0.getX(), p1.getY() - p0.getY());