Improve IconScaleTest

(cherry picked from commit bb6f5f0c)

platform/platform-tests/testSrc/com/intellij/util/ui/IconScaleTest.java

@@ -12,7 +12,6 @@ import com.intellij.util.ui.paint.AbstractPainter2DTest;
 import com.intellij.util.ui.paint.PaintUtilTest;
 import junit.framework.TestCase;
 import org.junit.After;
-import org.junit.Assume;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -21,6 +20,7 @@ import java.io.File;
 import java.net.MalformedURLException;
 
 import static com.intellij.util.ui.JBUI.ScaleType.SYS_SCALE;
+import static com.intellij.util.ui.JBUI.ScaleType.USR_SCALE;
 
 /**
  * Tests that {@link CachedImageIcon#scale(float)} doesn't break the contract and scales correctly.
@@ -49,44 +49,51 @@ public class IconScaleTest {
 
   @Test
   public void test() throws MalformedURLException {
-    Assume.assumeFalse("Linux doesn't support JRE-HiDPI yet", SystemInfo.isLinux);
-    test(1.0);
-    test(2.0);
-    test(2.5);
-  }
+    final double[] SCALES = {1, 2, 2.5};
 
-  public void test(double sysScale) throws MalformedURLException {
-    final int BASE_SIZE = 16;
-    final float ICON_SCALE = 1.75f;
+    //
+    // 1) JRE-HiDPI
+    //
+    PaintUtilTest.overrideJreHiDPIEnabled(true);
+    if (!SystemInfo.isLinux) { // Linux doesn't support JRE-HiDPI yet
+      for (double s : SCALES) test(1, s);
+    }
+
+    //
+    // 2) IDE-HiDPI
+    //
+    PaintUtilTest.overrideJreHiDPIEnabled(false);
+    for (double s : SCALES) test(s, 1);
+  }
 
+  public void test(double usrScale, double sysScale) throws MalformedURLException {
+    JBUI.setUserScaleFactor((float)usrScale);
+    ScaleContext ctx = ScaleContext.create(SYS_SCALE.of(sysScale), USR_SCALE.of(usrScale));
 
+    final int ICON_BASE_SIZE = 16;
+    final int ICON_USER_SIZE = (int)Math.round(ICON_BASE_SIZE * ctx.getScale(USR_SCALE));
+    final int ICON_REAL_SIZE = (int)Math.round(ICON_USER_SIZE * ctx.getScale(SYS_SCALE));
 
-    PaintUtilTest.overrideJreHiDPIEnabled(true);
-    JBUI.setUserScaleFactor(1);
+    final float ICON_SCALE = 1.75f;
+    final int ICON_SCALED_USER_SIZE = Math.round(ICON_USER_SIZE * ICON_SCALE);
+    final int ICON_SCALED_REAL_SIZE = Math.round(ICON_REAL_SIZE * ICON_SCALE);
 
     CachedImageIcon icon = new CachedImageIcon(new File(getIconPath()).toURI().toURL());
-    icon.updateScale(SYS_SCALE.of(sysScale));
-    ScaleContext originalCtx = icon.getScaleContext().copy();
+    icon.updateScaleContext(ctx);
 
-    TestCase.assertEquals("unexpected icon user width", BASE_SIZE, icon.getIconWidth());
-    TestCase.assertEquals("unexpected icon user height", BASE_SIZE, icon.getIconHeight());
-    TestCase.assertEquals("unexpected icon real width", 0,
-                          Double.compare(BASE_SIZE * sysScale, ImageUtil.getRealWidth(IconUtil.toImage(icon))));
-    TestCase.assertEquals("unexpected icon real height", 0,
-                          Double.compare(BASE_SIZE * sysScale, ImageUtil.getRealHeight(IconUtil.toImage(icon))));
+    TestCase.assertEquals("unexpected icon user width", ICON_USER_SIZE, icon.getIconWidth());
+    TestCase.assertEquals("unexpected icon user height", ICON_USER_SIZE, icon.getIconHeight());
+    TestCase.assertEquals("unexpected icon real width", ICON_REAL_SIZE, ImageUtil.getRealWidth(IconUtil.toImage(icon)));
+    TestCase.assertEquals("unexpected icon real height", ICON_REAL_SIZE, ImageUtil.getRealHeight(IconUtil.toImage(icon)));
 
     Icon scaledIcon = icon.scale(ICON_SCALE);
-    TestCase.assertFalse("new instance of the icon is expected", icon == scaledIcon);
-    TestCase.assertEquals("ScaleContext of the original icon changed", originalCtx, icon.getScaleContext());
-
-    TestCase.assertEquals("unexpected icon user width", 0,
-                          Double.compare(BASE_SIZE * ICON_SCALE, scaledIcon.getIconWidth()));
-    TestCase.assertEquals("unexpected icon user height", 0,
-                          Double.compare(BASE_SIZE * ICON_SCALE, scaledIcon.getIconHeight()));
-    TestCase.assertEquals("unexpected icon real width", 0,
-                          Double.compare(BASE_SIZE * ICON_SCALE * sysScale, ImageUtil.getRealWidth(IconUtil.toImage(scaledIcon))));
-    TestCase.assertEquals("unexpected icon real height", 0,
-                          Double.compare(BASE_SIZE * ICON_SCALE * sysScale, ImageUtil.getRealHeight(IconUtil.toImage(scaledIcon))));
+    TestCase.assertNotSame("new instance of the icon is expected", icon, scaledIcon);
+    TestCase.assertEquals("ScaleContext of the original icon changed", ctx, icon.getScaleContext());
+
+    TestCase.assertEquals("unexpected scaled icon user width", ICON_SCALED_USER_SIZE, scaledIcon.getIconWidth());
+    TestCase.assertEquals("unexpected scaled icon user height", ICON_SCALED_USER_SIZE, scaledIcon.getIconHeight());
+    TestCase.assertEquals("unexpected scaled icon real width", ICON_SCALED_REAL_SIZE, ImageUtil.getRealWidth(IconUtil.toImage(scaledIcon)));
+    TestCase.assertEquals("unexpected scaled icon real height", ICON_SCALED_REAL_SIZE, ImageUtil.getRealHeight(IconUtil.toImage(scaledIcon)));
   }
 
   private String getIconPath() {