More tImagePNG 16-bpc support. All functions except for Save.

Modules/Image/Inc/Image/tImagePNG.h

@@ -116,8 +116,12 @@ class tImagePNG : public tBaseImage
 	};
 
 	// Saves the tImagePNG to the PNG file specified. The type of filename must be PNG. If tFormat is Auto, this
-	// function will decide the format. BPP24 if all image pixels are opaque and BPP32 otherwise. Returns the format
-	// that the file was saved in, or tFormat::Invalid if there was a problem. Since Invalid is 0, you can use an 'if'.
+	// function will decide the format. If the internal buffer is 8-bpc it will choose between BPP24 and BPP32 depending
+	// on opacity (BPP24 is all pixels are opaque). In the internal buffer is 16-bpc it chooses between BPP48 and BPP64.
+	// When tFormat is explicitly one of the BPPNN choices, it may need to convert the data. For example, if the
+	// internal buffer is 8-bpc and you choose to save BPP48 or BPP64 (both 16-bpc formats), a conversion must take
+	// place. Returns the format that the file was saved in, or tFormat::Invalid if there was a problem. Since Invalid
+	// is 0, you can use an 'if' to check success.
 	tFormat Save(const tString& pngFile, tFormat) const;
 	tFormat Save(const tString& pngFile, const SaveParams& = SaveParams()) const;
 
@@ -129,15 +133,17 @@ class tImagePNG : public tBaseImage
 	int GetHeight() const																								{ return Height; }
 	bool IsOpaque() const;
 
-	// After this call you are the owner of the pixels and must eventually delete[] them. This tImagePNG object is
-	// invalid afterwards.
-	tPixel4b* StealPixels();
+	// After this call you are the owner of the pixels and must eventually delete[] them. This call only returns the
+	// stolen pixel array if it was present. If it was, the tImagePNG object will be invalid afterwards.
+	tPixel4b* StealPixels8();
+	tPixel4s* StealPixels16();
+
 	tFrame* GetFrame(bool steal = true) override;
 	tPixel4b* GetPixels8() const																						{ return Pixels8; }
 	tPixel4s* GetPixels16() const																						{ return Pixels16; }
 
 	tPixelFormat GetPixelFormatSrc() const override																		{ return IsValid() ? PixelFormatSrc : tPixelFormat::Invalid; }
-	tPixelFormat GetPixelFormat() const override																		{ return IsValid() ? tPixelFormat::R8G8B8A8 : tPixelFormat::Invalid; }
+	tPixelFormat GetPixelFormat() const override																		{ return IsValid() ? PixelFormat : tPixelFormat::Invalid; }
 
 	// Returns the colour profile of the source file that was loaded. This may not match the current if, say, gamma
 	// correction was requested on load.

Modules/Image/Src/tImageICO.cpp

@@ -235,15 +235,17 @@ tFrame* tImageICO::CreateFrame(const uint8* cursor, int width, int height, int n
 	// ICO files may have embedded pngs.
 	if (icon->Header.Size == 0x474e5089)
 	{
-		tImagePNG pngImage(cursor, numBytes);
+		tImagePNG::LoadParams params;
+		tAssert(params.Flags & tImagePNG::LoadFlag_ForceToBpc8);
+		tImagePNG pngImage(cursor, numBytes, params);
 		if (!pngImage.IsValid())
 			return nullptr;
 
 		width = pngImage.GetWidth();
 		height = pngImage.GetHeight();
 		tAssert((width > 0) && (height > 0));
 
-		tPixel4b* pixels = pngImage.StealPixels();
+		tPixel4b* pixels = pngImage.StealPixels8();
 		bool isOpaque = pngImage.IsOpaque();
 
 		tFrame* newFrame = new tFrame;

Modules/Image/Src/tImagePNG.cpp

@@ -321,6 +321,8 @@ tImagePNG::tFormat tImagePNG::Save(const tString& pngFile, const SaveParams& par
 		case tFormat::Auto:				srcBytesPerPixel = IsOpaque() ? 3 : 4;	break;
 		case tFormat::BPP24_RGB_BPC8:	srcBytesPerPixel = 3;					break;
 		case tFormat::BPP32_RGBA_BPC8:	srcBytesPerPixel = 4;					break;
+		// BPP48_RGB_BPC16,		// 48-bit RGB.  3 16-bit components.
+		// BPP64_RGBA_BPC16,	// 64-bit RGBA. 4 16-bit components.
 	}
 	if (!srcBytesPerPixel)
 		return tFormat::Invalid;
@@ -389,7 +391,8 @@ tImagePNG::tFormat tImagePNG::Save(const tString& pngFile, const SaveParams& par
 		PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE
 	);
 
-	// Optional significant bit (sBIT) chunk.
+	// The sBIT chunk tells the decoder the number of significant bits in the pixel data. It is optional
+	// as the data is still stored as either 8 or 16 bits per component,
 	png_color_8 sigBit;
 	sigBit.red = 8;
 	sigBit.green = 8;
@@ -456,14 +459,24 @@ bool tImagePNG::IsOpaque() const
 				return false;
 		}
 	}
-	// @wip Else do the 16 bpc.
+	else if (Pixels16)
+	{
+		for (int p = 0; p < (Width*Height); p++)
+		{
+			if (Pixels16[p].A < 65535)
+				return false;
+		}
+	}
 
 	return true;
 }
 
 
-tPixel4b* tImagePNG::StealPixels()
+tPixel4b* tImagePNG::StealPixels8()
 {
+	if (!Pixels8)
+		return nullptr;
+
 	tPixel4b* pixels = Pixels8;
 	Pixels8 = nullptr;
 	Width = 0;
@@ -472,4 +485,17 @@ tPixel4b* tImagePNG::StealPixels()
 }
 
 
+tPixel4s* tImagePNG::StealPixels16()
+{
+	if (!Pixels16)
+		return nullptr;
+
+	tPixel4s* pixels = Pixels16;
+	Pixels16 = nullptr;
+	Width = 0;
+	Height = 0;
+	return pixels;
+}
+
+
 }

UnitTests/Src/TestImage.cpp

@@ -852,7 +852,7 @@ tTestUnit(ImageRotation)
 	// Test writing rotated images.
 	tImagePNG aropng("TestData/Images/PNG/RightArrow.png");
 	int w = aropng.GetWidth(); int h = aropng.GetHeight();
-	tPicture aroPic(w, h, aropng.StealPixels(), false);
+	tPicture aroPic(w, h, aropng.StealPixels8(), false);
 	tRequire(aroPic.IsValid());
 
 	tPrintf("Image dimensions before rotate: W:%d H:%d\n", aroPic.GetWidth(), aroPic.GetHeight());
@@ -891,7 +891,7 @@ tTestUnit(ImageRotation)
 	tPrintf("Test 'plane' rotation.\n");
 	tImagePNG planepng("TestData/Images/PNG/plane.png");
 	w = planepng.GetWidth(); h = planepng.GetHeight();
-	tPicture planePic(w, h, planepng.StealPixels(), false);
+	tPicture planePic(w, h, planepng.StealPixels8(), false);
 	w = planePic.GetWidth();
 	h = planePic.GetHeight();
 	planePic.RotateCenter(-tMath::PiOver4, tColour4b::transparent);