Fix missing item images clipping in formspecs (#8652)

* Fix clipping of itemimage

* Code style

* More code styling

src/client/hud.cpp

@@ -649,10 +649,31 @@ void drawItemStack(video::IVideoDriver *driver,
 		core::rect<s32> oldViewPort = driver->getViewPort();
 		core::matrix4 oldProjMat = driver->getTransform(video::ETS_PROJECTION);
 		core::matrix4 oldViewMat = driver->getTransform(video::ETS_VIEW);
+		core::rect<s32> viewrect = rect;
+		if (clip)
+			viewrect.clipAgainst(*clip);
+
 		core::matrix4 ProjMatrix;
-		ProjMatrix.buildProjectionMatrixOrthoLH(2, 2, -1, 100);
+		ProjMatrix.buildProjectionMatrixOrthoLH(2.0f, 2.0f, -1.0f, 100.0f);
+
+		core::matrix4 ViewMatrix;
+		ViewMatrix.buildProjectionMatrixOrthoLH(
+			2.0f * viewrect.getWidth() / rect.getWidth(),
+			2.0f * viewrect.getHeight() / rect.getHeight(),
+			-1.0f,
+			100.0f);
+		ViewMatrix.setTranslation(core::vector3df(
+			1.0f * (rect.LowerRightCorner.X + rect.UpperLeftCorner.X -
+					viewrect.LowerRightCorner.X - viewrect.UpperLeftCorner.X) /
+					viewrect.getWidth(),
+			1.0f * (viewrect.LowerRightCorner.Y + viewrect.UpperLeftCorner.Y -
+					rect.LowerRightCorner.Y - rect.UpperLeftCorner.Y) /
+					viewrect.getHeight(),
+			0.0f));
+
 		driver->setTransform(video::ETS_PROJECTION, ProjMatrix);
-		driver->setTransform(video::ETS_VIEW, ProjMatrix);
+		driver->setTransform(video::ETS_VIEW, ViewMatrix);
+
 		core::matrix4 matrix;
 		matrix.makeIdentity();
 
@@ -662,7 +683,7 @@ void drawItemStack(video::IVideoDriver *driver,
 		}
 
 		driver->setTransform(video::ETS_WORLD, matrix);
-		driver->setViewPort(rect);
+		driver->setViewPort(viewrect);
 
 		video::SColor basecolor =
 			client->idef()->getItemstackColor(item, client);