Handout

kernel/device/graphicsstream.h

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+/*! \file
+ *  \brief \ref GraphicsStream, a \ref Graphics "graphical" \ref OutputStream
+ * "output stream" inspired by (and compatible to) \ref TextStream
+ */
+
+#pragma once
+
+#include "../graphics/primitives.h"
+#include "../object/outputstream.h"
+#include "./graphics.h"
+
+/*! \brief Output text (form different data type sources) on screen in \ref
+ * Graphics "graphic mode" (similar to \ref TextStream)
+ * \ingroup gfx
+ * \ingroup io
+ *
+ * Enables output of different data types using a monospaced font on a
+ * predefined area of the screen with activated graphics mode.
+ */
+class GraphicsStream : public OutputStream {
+	// Prevent copies and assignments
+	GraphicsStream(const GraphicsStream&) = delete;
+	GraphicsStream& operator=(const GraphicsStream&) = delete;
+
+	struct Cell {
+		char character;
+		Color color;
+	};
+
+	Cell* cell;
+	unsigned offset;
+
+	unsigned x, y;	///< Cursor position
+
+   protected:
+	/*! \brief Output the buffer contents of the base class \ref Stringbuffer
+	 *
+	 * The method is automatically called when the buffer is full,
+	 * but can also be called explicitly to force output of the current buffer.
+	 */
+	void flush();
+
+   public:
+	Font* const FONT;		 ///< Default font
+	const Point START;		 ///< Upper left corner of the window
+	const unsigned ROWS;	 ///< Number of rows in the window
+	const unsigned COLUMNS;	 ///< Number of columns in the window
+
+	/*! \brief CGA color palette
+	 */
+	static const Color BLACK, BLUE, GREEN, CYAN, RED, MAGENTA, BROWN,
+		LIGHT_GREY, DARK_GREY, LIGHT_BLUE, LIGHT_GREEN, LIGHT_CYAN, LIGHT_RED,
+		LIGHT_MAGENTA, YELLOW, WHITE;
+
+	/*! \brief Constructor
+	 *
+	 * Creates a window (= area on the screen) for text output.
+	 * Within the window text uses a virtual (invisible) cursor to offer a
+	 * very similar behavior to \ref TextStream -- including automatic
+	 * scrolling and column/row based positioning.
+	 *
+	 * \param start Coordinate of the upper left corner for the output window
+	 * \param width Width of the output window
+	 * \param height Height of the output window
+	 * \param font Font used for output text (or `nullptr` for default font)
+	 */
+	GraphicsStream(const Point& start, unsigned width, unsigned height,
+				   Font* font = nullptr);
+
+	/*! \brief Set the cursor position
+	 *
+	 *  \param x Column in window
+	 *  \param y Row in window
+	 */
+	void setPos(int x, int y);
+
+	/*! \brief Read the current cursor position
+	 *
+	 *  \param x Column in window
+	 *  \param y Row in window
+	 */
+	void getPos(int& x, int& y) const;
+
+	/*! \brief Display multiple characters in the window starting at the current
+	 * cursor position
+	 *
+	 * This method can be used to output a string, starting at the current
+	 * cursor position. Since the string does not need to contain a '\0'
+	 * termination (as it is usually the case in C), the parameter `length` is
+	 * required to specify the number of characters in the string. When the
+	 * output is complete, the cursor will be positioned after the last
+	 * character printed. The entire text uniformly has the color `color`
+	 *
+	 * If there is not enough space left at the end of the line, the output will
+	 * be continued on the following line. As soon as the last window line is
+	 * filled, the entire window area will be moved up one line.
+	 * The first line disappears and the last line is blank, continuing output
+	 * there.
+	 *
+	 * A line break will also occurs wherever the character `\\n` is inserted
+	 * in the text to be output.
+	 *
+	 *  \param str String to output
+	 *  \param length length of string
+	 *  \param color Foreground color of string
+	 */
+	void print(char* str, int length, const Color& color = LIGHT_GREY);
+
+	/*! \brief Clear window and reset cursor
+	 *
+	 *  \param character Filling character
+	 *  \param color Foreground color
+	 */
+	void reset(char character = ' ', const Color& color = LIGHT_GREY);
+
+	/*! \brief Basic output of a (colored) character at a certain position on
+	 * the screen.
+	 *
+	 * Outputs `character` at the absolute position (`x`, `y`) with the
+	 * specified color: `x` specifies the column and `y` the row of the desired
+	 * position, with 0 ≤ x < \ref COLUMNS and 0 ≤ `y` < \ref ROWS.
+	 * The position (0,0) indicates the upper left corner of the window (at
+	 * the coordinates \ref START).
+	 *
+	 *  \param x Column for output of the character
+	 *  \param y Row for output of the character
+	 *  \param character Character to be output
+	 *  \param color Foreground color
+	 */
+	void show(int x, int y, char character, const Color& color = LIGHT_GREY);
+
+	/*! \brief Draw using the \ref Graphics device
+	 */
+	void draw();
+};