Merge pull request #357 from ThemiraChathumina/hoverRendering

Improve the hover content rendering

Author: NipunaRanasinghe

src/main/java/org/wso2/lsp4intellij/utils/GUIUtils.java

@@ -38,10 +38,15 @@
 import org.wso2.lsp4intellij.extensions.LSPExtensionManager;
 import org.wso2.lsp4intellij.contributors.label.LSPLabelProvider;
 
-import javax.swing.*;
+import javax.swing.JTextPane;
 import javax.swing.event.HyperlinkEvent;
+import javax.swing.text.StyleConstants;
+import javax.swing.text.html.HTMLDocument;
 import javax.swing.text.html.HTMLEditorKit;
-import java.awt.*;
+import javax.swing.text.html.StyleSheet;
+
+import java.awt.Color;
+import java.awt.Point;
 import java.net.URISyntaxException;
 import java.util.Objects;
 import java.util.Optional;
@@ -67,6 +72,56 @@ public static Hint createAndShowEditorHint(Editor editor, String string, Point p
         return createAndShowEditorHint(editor, string, point, HintManager.ABOVE, flags);
     }
 
+    private static StyleSheet getStyleSheet(JTextPane textPane) {
+        HTMLDocument doc = (HTMLDocument) textPane.getDocument();
+        return doc.getStyleSheet();
+    }
+
+    private static void configureTextStyles(JTextPane textPane) {
+        String fontFamily = "Arial";
+        int fontSize = 10;
+
+        StyleSheet styleSheet = getStyleSheet(textPane);
+
+        styleSheet.addRule("p { font-family: Segoe UI Semibold; font-size: " + fontSize + "px; }");
+        styleSheet.addRule("li { font-family: Segoe UI Semibold; font-size: " + fontSize + "px; }");
+        styleSheet.addRule(
+                "code { font-family: " + fontFamily + "; font-weight: bold; font-size: " + fontSize + "px; }");
+
+        for (int i = 1; i <= 6; i++) {
+            styleSheet.addRule("h" + i + " { font-family: " + fontFamily + "; font-weight: bold; }");
+        }
+    }
+
+    private static void adjustWidth(JTextPane textPane) {
+        int width = textPane.getPreferredSize().width;
+        if (width > 600) {
+            getStyleSheet(textPane).addRule("p { width: 600px; }");
+        }
+    }
+
+    private static void addPaddingToCodeBlocks(JTextPane textPane, String text) {
+        text = text.replace("<code>", "<code>&nbsp;")
+                .replaceAll("(?<!\\n)</code>", "&nbsp;</code>");
+
+        textPane.setText(text);
+    }
+
+    private static void setCodeBlockBackgroundColor(JTextPane textPane) {
+        StyleSheet styleSheet = getStyleSheet(textPane);
+
+        Color bodyFontColor = styleSheet.getStyle("body").getAttribute(StyleConstants.Foreground) instanceof Color
+                ? (Color) styleSheet.getStyle("body").getAttribute(StyleConstants.Foreground) : Color.BLACK;
+
+        Color inverseColor = new Color(255 - bodyFontColor.getRed(),
+                            255 - bodyFontColor.getGreen(),
+                            255 - bodyFontColor.getBlue()).darker();
+
+        String hexColor = String.format("#%02x%02x%02x", inverseColor.getRed(), inverseColor.getGreen(), inverseColor.getBlue());
+
+        styleSheet.addRule("code { background-color: " + hexColor + "; }");
+    }
+
     /**
      * Shows a hint in the editor
      *
@@ -80,12 +135,12 @@ public static Hint createAndShowEditorHint(Editor editor, String string, Point p
     public static Hint createAndShowEditorHint(Editor editor, String string, Point point, short constraint, int flags) {
         JTextPane textPane = new JTextPane();
         textPane.setEditorKit(new HTMLEditorKit());
-        textPane.setText(string);
-        int width = textPane.getPreferredSize().width;
-        if (width > 600) {
-            // max-width does not seem to be supported, so use this rather ugly hack...
-            textPane.setText(string.replace("<style>", "<style>p {width: 600px}\n"));
-        }
+
+        addPaddingToCodeBlocks(textPane, string);
+        configureTextStyles(textPane);
+        setCodeBlockBackgroundColor(textPane);
+        adjustWidth(textPane);
+
         textPane.setEditable(false);
         textPane.addHyperlinkListener(e -> {
             if ((e.getEventType() == HyperlinkEvent.EventType.ACTIVATED)
@@ -138,5 +193,4 @@ public static LSPLabelProvider getLabelProviderFor(LanguageServerDefinition serv
         return IntellijLanguageClient.getExtensionManagerForDefinition(serverDefinition)
                 .map(LSPExtensionManager::getLabelProvider).orElse(DEFAULT_LABEL_PROVIDER);
     }
-
 }