Fix drawing of B_GRAY1 bitmaps.

- Colors were reversed
- Padding was not handled properly because of a roundeing error

Add a test that shows the issue (behavior confirmed against BeOS)

Change-Id: I4c6e954fb6bdab92ad4e0e96897e78b26eb4727b
Reviewed-on: https://review.haiku-os.org/c/1025
Reviewed-by: Stephan Aßmus <[email protected]>

src/kits/interface/ColorConversion.cpp

@@ -546,7 +546,9 @@ uint32
 ReadGray1(const uint8 **source, int32 index)
 {
 	int32 shift = 7 - (index % 8);
-	uint32 result = ((**source >> shift) & 0x01) ? 0xff : 0x00;
+	// In B_GRAY1, a set bit means black (highcolor), a clear bit means white
+	// (low/view color). So we map them to 00 and 0xFF, respectively.
+	uint32 result = ((**source >> shift) & 0x01) ? 0x00 : 0xFF;
 	if (shift == 0)
 		(*source)++;
 	return result;
@@ -656,8 +658,8 @@ ConvertBits(const srcByte *srcBits, dstByte *dstBits, int32 srcBitsLength,
 		return B_OK;
 	}
 
-	int32 srcLinePad = (srcBitsPerRow - width * srcBitsPerPixel) >> 3;
-	int32 dstLinePad = (dstBitsPerRow - width * dstBitsPerPixel) >> 3;
+	int32 srcLinePad = (srcBitsPerRow - width * srcBitsPerPixel + 7) >> 3;
+	int32 dstLinePad = (dstBitsPerRow - width * dstBitsPerPixel + 7) >> 3;
 	uint32 result;
 	uint32 source;
 

src/tests/kits/interface/Jamfile

@@ -67,17 +67,6 @@ ObjectDefines
 	: BCheckBox=HCheckBox
 	;
 
-SimpleTest ScrollViewTest_r5 :
-	ScrollViewTest.cpp
-	: be [ TargetLibsupc++ ]
-	;
-
-SimpleTest ScrollViewTest :
-	ScrollViewTest.cpp
-	ScrollView.cpp
-	: be [ TargetLibsupc++ ]
-	;
-
 SimpleTest AlertTest :
 	SimpleAlertTest.cpp
 	: be [ TargetLibsupc++ ]
@@ -101,6 +90,10 @@ SimpleTest ControlLookTest :
 	: be [ TargetLibsupc++ ]
 	;
 
+SimpleTest DrawBitmapTest :
+	DrawBitmapTest.cpp
+	: be ;
+
 SimpleTest ListViewTest :
 	ListViewTest.cpp
 	: be [ TargetLibsupc++ ]
@@ -111,6 +104,17 @@ SimpleTest ScreenTest :
 	: be
 	;
 
+SimpleTest ScrollViewTest_r5 :
+	ScrollViewTest.cpp
+	: be [ TargetLibsupc++ ]
+	;
+
+SimpleTest ScrollViewTest :
+	ScrollViewTest.cpp
+	ScrollView.cpp
+	: be [ TargetLibsupc++ ]
+	;
+
 SimpleTest StatusBarTest :
 	StatusBarTest.cpp
 	: be [ TargetLibsupc++ ]

src/tests/kits/interface/bbitmap/DrawBitmapTest.cpp

@@ -0,0 +1,90 @@
+/*
+ * Copyright 2019, Adrien Destugues <[email protected]>
+ * Distributed under terms of the MIT license.
+ */
+
+
+#include <Application.h>
+#include <Bitmap.h>
+#include <View.h>
+#include <Window.h>
+
+#include <assert.h>
+
+
+class BitmapView: public BView
+{
+	public:
+		BitmapView(BBitmap* bitmap)
+			: BView(bitmap->Bounds(), "test view", B_FOLLOW_LEFT_TOP, B_WILL_DRAW)
+			, fBitmap(bitmap)
+		{
+		}
+
+		~BitmapView()
+		{
+			delete fBitmap;
+		}
+
+		void Draw(BRect updateRect)
+		{
+			DrawBitmap(fBitmap);
+		}
+
+	private:
+		BBitmap* fBitmap;
+};
+
+
+int
+main(void)
+{
+	BApplication app("application/Haiku-BitmapTest");
+
+	BWindow* window = new BWindow(BRect(10, 10, 100, 100),
+		"Bitmap drawing test", B_DOCUMENT_WINDOW, B_QUIT_ON_WINDOW_CLOSE);
+	window->Show();
+
+	BBitmap* bitmap = new BBitmap(BRect(0, 0, 24, 24), B_GRAY1);
+
+	// Bitmap is 25 pixels wide, which rounds up to 4 pixels
+	// The last byte only has one bit used, and 7 bits of padding
+	assert(bitmap->BytesPerRow() == 4);
+
+	// This was extracted from letter_a.pbm and should look mostly like a
+	// black "A" letter on a white background (confirmed BeOS behavior)
+	const unsigned char data[] = {
+		0, 0, 0, 0,
+		0, 8, 0, 0,
+		0, 0x1c, 0, 0,
+		0, 0x3e, 0, 0,
+		0, 0x7e, 0, 0,
+		0, 0xFF, 0, 0,
+		0, 0xE7, 0, 0,
+		0, 0xC3, 0, 0,
+		1, 0xC3, 0x80, 0,
+		1, 0x81, 0x80, 0,
+		3, 0x81, 0xC0, 0,
+		3, 0xFF, 0xC0, 0,
+		7, 0xFF, 0xE0, 0,
+		7, 0xFF, 0xE0, 0,
+		7, 0x81, 0xE0, 0,
+		0x0F, 0, 0x0F, 0,
+		0x0F, 0, 0x0F, 0,
+		0x1F, 0, 0xF8, 0,
+		0x1E, 0, 0x78, 0,
+		0x1C, 0, 0x38, 0,
+		0x3C, 0, 0x3C, 0,
+		0x3C, 0, 0x3C, 0,
+		0x38, 0, 0x0E, 0,
+		0x78, 0, 0x0F, 0,
+		0, 0, 0, 0
+	};
+	bitmap->SetBits(data, sizeof(data), 0, B_GRAY1);
+
+	BView* view = new BitmapView(bitmap);
+	window->AddChild(view);
+
+	app.Run();
+	return 0;
+}