fake screen for testing

include/fakescreen.h

@@ -0,0 +1,21 @@
+#include "screen.h"
+
+class FakeScreen : public ScreenShot {
+private:
+	int xoffset = 0;
+	int yoffset = 0;
+	int xsize = 0;
+	int ysize = 0;
+public:
+
+	FakeScreen(int xoffset = 0, int yoffset = 0, int xsize = 0, int ysize = 0);
+	~FakeScreen();
+
+	virtual void take(cv::Mat& cvimg) override;
+	virtual void operator() (cv::Mat& cvimg) override;
+
+	virtual int getXOffset() const override;
+	virtual int getYOffset() const override;
+	virtual double getXScale() const override;
+	virtual double getYScale() const override;
+};

include/screen.h

@@ -33,28 +33,17 @@ public:
 
 	ScreenShot();
 	ScreenShot(Display* d, Window w);
-	~ScreenShot();
+	virtual ~ScreenShot();
 
-	void take(cv::Mat& cvimg);
-	void operator() (cv::Mat& cvimg);
+	virtual void take(cv::Mat& cvimg);
+	virtual void operator() (cv::Mat& cvimg);
 
 	constexpr operator bool () const {
 		return valid;
 	}
 
-	constexpr int getXOffset() const {
-		return wattrib.x;
-	}
-
-	constexpr int getYOffset() const {
-		return wattrib.y;
-	}
-
-	constexpr double getXScale() const {
-		return wattrib.width / (double) DEFAULTWIDTH;
-	}
-
-	constexpr double getYScale() const {
-		return wattrib.height / (double) DEFAULTHEIGHT;
-	}
+	virtual int getXOffset() const;
+	virtual int getYOffset() const;
+	virtual double getXScale() const;
+	virtual double getYScale() const;
 };

src/fakescreen.cpp

@@ -0,0 +1,38 @@
+#include "fakescreen.h"
+
+FakeScreen::FakeScreen(int xoffset, int yoffset, int xsize, int ysize) : ScreenShot(),
+	xoffset(xoffset), yoffset(yoffset), xsize(xsize), ysize(ysize) {
+}
+
+FakeScreen::~FakeScreen() {}
+
+
+void FakeScreen::take(cv::Mat& cvimg) {
+	// take screenshot from entire screen using base class
+	cv::Mat entireScreen;
+	ScreenShot::take(entireScreen);
+
+	// only return part of the screenshot
+	entireScreen({yoffset, yoffset + ysize}, {xoffset, xoffset + xsize}).copyTo(cvimg);
+}
+
+void FakeScreen::operator() (cv::Mat& cvimg) {
+	take(cvimg);
+}
+
+
+int FakeScreen::getXOffset() const {
+	return xoffset;
+}
+
+int FakeScreen::getYOffset() const {
+	return yoffset;
+}
+
+double FakeScreen::getXScale() const {
+	return xsize / (double) DEFAULTWIDTH;
+}
+
+double FakeScreen::getYScale() const {
+	return ysize / (double) DEFAULTHEIGHT;
+}

src/screen.cpp

@@ -139,3 +139,20 @@ ScreenShot::~ScreenShot() {
 	if (closeDisp)
 		XCloseDisplay(display);
 }
+
+
+int ScreenShot::getXOffset() const {
+	return wattrib.x;
+}
+
+int ScreenShot::getYOffset() const {
+	return wattrib.y;
+}
+
+double ScreenShot::getXScale() const {
+	return wattrib.width / (double) DEFAULTWIDTH;
+}
+
+double ScreenShot::getYScale() const {
+	return wattrib.height / (double) DEFAULTHEIGHT;
+}