[Win32] Consider SWT.DRAW_DELIMITER flag when drawing text with GDI+

The GC.drawText() implementation falls back to using GDI instead of GDI+
(even if enabled) in many cases for historic reasons. There were issues
with rendering tabs back then. One of the few cases where GDI+ is used
is when glyphs that are non existing for GDI are used. In that case,
however, the DRAW_DELIMITER flag is not properly considered. The
behavior is always as if the flag was enabled, i.e., line delimiters is
always drawn even if the flag is not set.

This change corrects the behavior of the GDI+ text drawing
implementation to consider if the DRAW_DELIMITER flag is not set. In
consequence, strings with glyphs that are not supported by GDI are now
rendered without line breaks if undesired as per defined flags.

Contributes to
#3091

Author: HeikoKlare

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/GC.java

@@ -3037,6 +3037,9 @@ private RectF drawText(long gdipGraphics, char[] buffer, int start, int length,
 private void drawTextGDIP(long gdipGraphics, String string, int x, int y, int flags, boolean draw, Point size) {
 	boolean needsBounds = !draw || (flags & SWT.DRAW_TRANSPARENT) == 0;
 	char[] buffer;
+	if ((flags & SWT.DRAW_DELIMITER) == 0) {
+		string = string.replaceAll("[\\r\\n]+", "");
+	}
 	int length = string.length();
 	if (length != 0) {
 		buffer = string.toCharArray();

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_graphics_GC.java

@@ -954,6 +954,18 @@ public void test_textExtentLjava_lang_StringI() {
 	assertEquals(SWT.ERROR_GRAPHIC_DISPOSED, e.code);
 }
 
+@Test
+public void test_textExtentLjava_lang_StringI_disabledLineDelimiter() {
+	gc.setAdvanced(false);
+	Point ptWithoutAdvanced = gc.textExtent("abc\u4E2D" + System.lineSeparator() + "def", 0);
+	gc.setAdvanced(true);
+	Point ptWithAdvanced = gc.textExtent("abc\u4E2D" + System.lineSeparator() + "def", 0);
+	// Due to slightly different rendering, size must not be identical but similar in advanced/non-advanced mode
+	assertTrue(Math.abs(ptWithAdvanced.x - ptWithoutAdvanced.x) <= 2);
+	assertTrue(Math.abs(ptWithAdvanced.y - ptWithoutAdvanced.y) <= 2);
+	gc.dispose();
+}
+
 @Test
 public void test_toString() {
 	String s = gc.toString();