Fix #467: Paste as HTML collapses white spaces

Author: mihnita

bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/HTMLWriter.java

@@ -37,8 +37,8 @@ public HTMLWriter(StyledText styledText, int start, int length) {
 	@Override
 	public void close() {
 		if (!isClosed()) {
-			write("</div>\n");
-			write("</div>\n");
+			write("</div>");
+			write("</div>");
 			super.close();
 		}
 	}
@@ -52,29 +52,27 @@ void writeHeader() {
 		appendStyle(innerDivStyle, "color:", styledText.getForeground(), ";");
 		appendStyle(innerDivStyle, "background-color:", styledText.getBackground(), ";");
 
-		appendStyle(outerDivStyle, "padding-left:", styledText.getLeftMargin(), "px;");
-		appendStyle(outerDivStyle, "padding-top:", styledText.getTopMargin(), "px;");
-		appendStyle(outerDivStyle, "padding-right:", styledText.getRightMargin(), "px;");
-		appendStyle(outerDivStyle, "padding-bottom:", styledText.getBottomMargin(), "px;");
+		appendStyle(outerDivStyle, "padding:"
+						+ styledText.getTopMargin() + "px "
+						+ styledText.getRightMargin() + "px "
+						+ styledText.getBottomMargin() + "px "
+						+ styledText.getLeftMargin() + "px;");
 
 		String language = appendFont(innerDivStyle, styledText.getFont(), 0);
 
-		// Using wrapIndent like this messes up the line background (if set).
-//		int wrapIndent = styledText.getWrapIndent();
-//		if (wrapIndent != 0) {
-//			appendStyle(globalStyle, "padding-left:", wrapIndent, "px;");
-//		}
-//		int indent = styledText.getIndent() - wrapIndent;
 		int indent = styledText.getIndent();
 		if (indent != 0) {
 			appendStyle(innerDivStyle, "text-indent:", indent, "px;");
 		}
 
-		// TODO?
-//		int lineSpacing = styledText.getLineSpacing();
-
-		if (!styledText.getWordWrap()) {
-			appendStyle(innerDivStyle, "white-space:nowrap;");
+		if (styledText.getWordWrap()) {
+			// Sequences of white space are preserved.
+			// Lines are broken at newline characters, at <br>, and as necessary to fill line boxes.
+			appendStyle(innerDivStyle, "white-space:pre-wrap;");
+		} else {
+			// Sequences of white space are preserved.
+			// Lines are only broken at newline characters in the source and at <br> elements.
+			appendStyle(innerDivStyle, "white-space:pre;");
 		}
 
 		appendAlignAndJustify(innerDivStyle, styledText.getAlignment(), styledText.getJustify());
@@ -83,17 +81,11 @@ void writeHeader() {
 			appendStyle(innerDivStyle, "direction:rtl;");
 		}
 
-		// Do we have any use for these?
-//		Color selectionBackground = styledText.getSelectionBackground();
-//		Color selectionForeground = styledText.getSelectionForeground();
-//		int tabs = styledText.getTabs();
-//		boolean blockSelection = styledText.getBlockSelection();
-
-		write("<div style='" + outerDivStyle + "'>\n");
+		write("<div style='" + outerDivStyle + "'>");
 		if (language == null || language.isEmpty()) {
-			write("<div style='" + innerDivStyle + "'>\n");
+			write("<div style='" + innerDivStyle + "'>");
 		} else {
-			write("<div lang='" + language + "' style='" + innerDivStyle + "'>\n");
+			write("<div lang='" + language + "' style='" + innerDivStyle + "'>");
 		}
 	}
 
@@ -102,7 +94,7 @@ public void writeLineDelimiter(String lineDelimiter) {
 		if (isClosed()) {
 			SWT.error(SWT.ERROR_IO);
 		}
-		write(lineDelimiter);
+		// We don't write the newline, otherwise it would be rendered because of the `white-space:pre;`.
 	}
 
 	@Override
@@ -117,8 +109,11 @@ String writeLineStart(Color lineBackground, int indent, int verticalIndent, int
 			appendStyle(paragraphStyle, "text-indent:", indent, "px;");
 		}
 
-		if (verticalIndent != 0) {
-			appendStyle(paragraphStyle, "margin-top:", verticalIndent, "px;");
+		if (verticalIndent == 0) {
+			appendStyle(paragraphStyle, "margin:0;");
+		} else {
+			// Set the margin-top to verticalIndent, everything else zero.
+			appendStyle(paragraphStyle, "margin:", verticalIndent, " 0 0 0;");
 		}
 
 		if (paragraphStyle.length() == 0) {
@@ -131,6 +126,11 @@ String writeLineStart(Color lineBackground, int indent, int verticalIndent, int
 		return "</p>";
 	}
 
+	@Override
+	void writeEmptyLine() {
+		write("<br>");
+	}
+
 	@Override
 	String writeSpanStart(StyleRange style) {
 		StringBuilder spanStyle = new StringBuilder();

bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/RTFWriter.java

@@ -135,6 +135,11 @@ String writeLineStart(Color lineBackground, int indent, int verticalIndent, int
 		return lineBackground == null ? "" : "}";
 	}
 
+	@Override
+	void writeEmptyLine() {
+		// Do nothing. RTF does not need special treatment for empty paragraph.
+	}
+
 	@Override
 	String writeSpanStart(StyleRange style) {
 		write("{\\cf");

bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/StyledTextWriterBase.java

@@ -149,6 +149,7 @@ void writeStyledLine(String line, int lineOffset, int ranges[], StyleRange[] sty
 		int endOffset = startOffset + super.getCharCount();
 		int lineEndOffset = Math.min(lineLength, endOffset - lineOffset);
 
+		int outTextLen = 0; // collect the length of the text we output (unescaped)
 		for (int i = 0; i < styles.length; i++) {
 			StyleRange style = styles[i];
 			int start, end;
@@ -173,6 +174,7 @@ void writeStyledLine(String line, int lineOffset, int ranges[], StyleRange[] sty
 				// style starting beyond end of write range or end of line
 				// is guarded against above.
 				writeEscaped(line, lineIndex, start);
+				outTextLen += start - lineIndex;
 				lineIndex = start;
 			}
 			// write styled text
@@ -183,6 +185,7 @@ void writeStyledLine(String line, int lineOffset, int ranges[], StyleRange[] sty
 			// guard against invalid styles and let style processing continue
 			copyEnd = Math.max(copyEnd, lineIndex);
 			writeEscaped(line, lineIndex, copyEnd);
+			outTextLen += copyEnd - lineIndex;
 
 			writeSpanEnd(atSpanEnd);
 
@@ -192,6 +195,11 @@ void writeStyledLine(String line, int lineOffset, int ranges[], StyleRange[] sty
 		// write the unstyled text at the end of the line
 		if (lineIndex < lineEndOffset) {
 			writeEscaped(line, lineIndex, lineEndOffset);
+			outTextLen += lineEndOffset - lineIndex;
+		}
+
+		if (outTextLen == 0) {
+			writeEmptyLine();
 		}
 
 		writeLineEnd(atLineEnd);
@@ -231,6 +239,13 @@ void writeLineEnd(String prepared) {
 		write(prepared);
 	}
 
+	/**
+	 * Invoked at the end of each line, writeLineEnd, if there was no text output.
+	 *
+	 * <p>This is needed for HTML, which does not render empty paragraphs.</p>
+	 */
+	abstract void writeEmptyLine();
+
 	/**
 	 * Invoked at the beginning of each styled span fragment in the original widget.
 	 *