dispmanx: fix grabber issues with certain widths and support cropping (#634)

* dispmanx: fix grabber issues with certain widths and support cropping

The dispmanx grabber will produce garbage output if the destination
pitch is not set to a multiple of 64 bytes (16 RGBA pixels).

It can also fail when retrieving only a part of the image
(eg in 3DSBS or TAB mode).

Handle these cases by capturing the full image into a separate
buffer with the pitch set to an appropriate value and manually
handle 3D SBS/TAB left/top half copying.

At this point supporting cropping like in the V4L2 grabber is
rather easy and added as well. This'll help handling overscan
setups (old TVs) and removing (possibly asymmetric) overscan
borders.

Cropping is disabled in video capture mode (when the
DISPMANX_SNAPSHOT_FILL flag is set).

Signed-off-by: Matthias Reichl <hias@horus.com>

* hyperion-dispmanx: add optional crop values and 3D mode options

Signed-off-by: Matthias Reichl <hias@horus.com>

* hyperiond: support cropping on the dispmanx grabber

Honor cropLeft, cropRight, cropTop and cropBottom settings in
the framegrabber section of the conf file to control cropping.

Signed-off-by: Matthias Reichl <hias@horus.com>

Former-commit-id: bbb55f6621b90384e417f37da4f2543d112ef57a

include/grabber/DispmanxFrameGrabber.h

@@ -41,6 +41,9 @@ public:
 	///
 	void setVideoMode(const VideoMode videoMode);
 
+	void setCropping(const unsigned cropLeft, const unsigned cropRight,
+			 const unsigned cropTop, const unsigned cropBottom);
+
 	///
 	/// Captures a single snapshot of the display and writes the data to the given image. The
 	/// provided image should have the same dimensions as the configured values (_width and
@@ -68,4 +71,17 @@ private:
 	const unsigned _width;
 	/// Height of the captured snapshot [pixels]
 	const unsigned _height;
+
+	// the selected VideoMode
+	VideoMode _videoMode;
+
+	// number of pixels to crop after capturing
+	unsigned _cropLeft, _cropRight, _cropTop, _cropBottom;
+
+	// temp buffer when capturing with unsupported pitch size or
+	// when we need to crop the image
+	ColorRgba* _captureBuffer;
+
+	// size of the capture buffer in Pixels
+	unsigned _captureBufferSize;
 };

include/grabber/DispmanxWrapper.h

@@ -56,6 +56,9 @@ public slots:
 	///
 	void stop();
 
+	void setCropping(const unsigned cropLeft, const unsigned cropRight,
+		const unsigned cropTop, const unsigned cropBottom);
+
 	///
 	/// Set the grabbing mode
 	/// @param[in] mode The new grabbing mode