CCanvas.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2020, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */
#pragma once

#include <mrpt/core/exceptions.h>
#include <mrpt/img/TColor.h>
#include <mrpt/math/math_frwds.h>
#include <cmath>  // sin() cos()

namespace mrpt::img
{
class CImage;

/** This virtual class defines the interface of any object accepting drawing
 * primitives on it.
 *
 *  A number of text fonts can be selected with CCanvas::selectTextFont(). These
 * are the
 *   implemented font names:
 *
 *  - "6x13"
 *  - "6x13B" (bold)
 *  - "6x13O" (italic)
 *  - "9x15"
 *  - "9x15B" (bold)
 *  - "10x20"
 *  - "18x18ja" (Japanese, UNICODE character values)
 *
 *  For an example of each font check the <a
 * href="http://www.mrpt.org/Implemented_2D_Fonts">corresponding wiki page</a>.
 *
 * \sa CImage
 * \ingroup mrpt_img_grp
 */
class CCanvas
{
   protected:
    /** The selected font name. */
    std::string m_selectedFont{"9x15"};

    /** Direct access to character bitmaps. */
    const uint32_t* m_selectedFontBitmaps{nullptr};

   public:
    CCanvas() = default;
    virtual ~CCanvas() = default;

    /** Definition of pen styles */
    enum TPenStyle
    {
        psSolid = 0,
        psDash, /* -------  */
        psDot, /* .......  */
        psDashDot, /* _._._._  */
        psDashDotDot /* _.._.._  */
    };

    /** Changes the value of the pixel (x,y).
     *  Pixel coordinates starts at the left-top corner of the image, and start
     * in (0,0).
     *  The meaning of the parameter "color" depends on the implementation: it
     * will usually
     *   be a 24bit RGB value (0x00RRGGBB), but it can also be just a 8bit gray
     * level.
     *
     *  You can also use a TColor() type as input and it will be automatically
     * converted to size_t.
     *
     *  This method must support (x,y) values OUT of the actual image size
     * without neither
     *   raising exceptions, nor leading to memory access errors.
     *
     */
    virtual void setPixel(int x, int y, size_t color) = 0;

    /** Returns the width of the image in pixels
     */
    virtual size_t getWidth() const = 0;

    /** Returns the height of the image in pixels
     */
    virtual size_t getHeight() const = 0;

    /** Draws a line.
     * \param x0 The starting point x coordinate
     * \param y0 The starting point y coordinate
     * \param x1 The end point x coordinate
     * \param y1 The end point y coordinate
     * \param color The color of the line
     * \param width The desired width of the line (this is IGNORED in this
     * virtual class)
     *  This method may be redefined in some classes implementing this
     * interface in a more appropiate manner.
     */
    virtual void line(
        int x0, int y0, int x1, int y1, const mrpt::img::TColor color,
        unsigned int width = 1, TPenStyle penStyle = psSolid);

    /** Draws a rectangle (an empty rectangle, without filling)
     * \param x0 The top-left x coordinate
     * \param y0 The top-left y coordinate
     * \param x1 The right-bottom x coordinate
     * \param y1 The right-bottom y coordinate
     * \param color The color of the line
     * \param width The desired width of the line.
     * \sa filledRectangle
     */
    void rectangle(
        int x0, int y0, int x1, int y1, const mrpt::img::TColor color,
        unsigned int width = 1);

    /** Draws a triangle
     * \param x0 The triangle center x coordinate
     * \param y0 The triangle center y coordinate
     * \param size The size of the triangle
     * \param color The color of the line
     *  \param inferior The position of the triangle
     * \param width The desired width of the line.
     * \sa triangle
     */
    void triangle(
        int x0, int y0, int size, const mrpt::img::TColor color,
        bool inferior = true, unsigned int width = 1);

    /** Draws a filled rectangle.
     * \param x0 The top-left x coordinate
     * \param y0 The top-left y coordinate
     * \param x1 The right-bottom x coordinate
     * \param y1 The right-bottom y coordinate
     * \param color The color of the rectangle fill
     *  This method may be redefined in some classes implementing this
     * interface in a more appropiate manner.
     * \sa rectangle
     */
    virtual void filledRectangle(
        int x0, int y0, int x1, int y1, const mrpt::img::TColor color);

    /** Renders 2D text using bitmap fonts.
     * \param x0 The x coordinates
     * \param y0 The y coordinates
     * \param str The string to put. If using UNICODE characters, use UTF-8
     * encoding.
     * \param color The text color
     *
     * \sa selectTextFont
     */
    virtual void textOut(
        int x0, int y0, const std::string& str, const mrpt::img::TColor color);

    /** Select the current font used when drawing text.
     * \param fontName The name of the font
     *
     *  Valid font names:
     *  - 5x7
     *  - 6x13
     *  - 6x13B
     *  - 6x13O
     *  - 9x15   (Default at start-up)
     *  - 9x15B
     *  - 10x20
     *  - 18x18ja (Asian characters for UTF-8 strings - Only available if MRPT
     * is built with MRPT_HAS_ASIAN_FONTS = true)
     *
     *   <img src="sample_textFonts.png" >
     *
     * \sa textOut, The example in <a
     * href="http://www.mrpt.org/Implemented_2D_Fonts">this page</a>.
     */
    virtual void selectTextFont(const std::string& fontName);

    /** Draws an image as a bitmap at a given position.
     * \param x0 The top-left corner x coordinates on this canvas where the
     * image is to be drawn
     * \param y0 The top-left corner y coordinates on this canvas where the
     * image is to be drawn
     * \param img The image to be drawn in this canvas
     *  This method may be redefined in some classes implementing this
     * interface in a more appropiate manner.
     */
    virtual void drawImage(int x, int y, const mrpt::img::CImage& img);

    /** Draw a mark.
     * \param x0 The point x coordinate
     * \param y0 The point y coordinate
     * \param color The color of the cross
     * \param size The size of the cross
     * \param type The cross type. It could be: 'x', '+', ':'(like '+' but
     * clear at the center dot), or 's' (square)
     * \param width The desired width of the cross (this is IGNORED yet)
     */
    void drawMark(
        int x0, int y0, const mrpt::img::TColor color, char type, int size = 5,
        unsigned int width = 1);

    /** Draws an image as a bitmap at a given position, with some custom scale
     * and rotation changes.
     * \param x0 The top-left corner x coordinates on this canvas where the
     * image is to be drawn
     * \param y0 The top-left corner y coordinates on this canvas where the
     * image is to be drawn
     * \param rotation The rotation in radians, positive values being
     * anti-clockwise direction, 0 is the normal position.
     * \param scale The scale factor, e.g. 2 means twice the original size.
     * \param img The image to be drawn in this canvas
     *  This method may be redefined in some classes implementing this
     * interface in a more appropiate manner.
     */
    virtual void drawImage(
        int x, int y, const mrpt::img::CImage& img, float rotation,
        float scale);

    /** Draws a circle of a given radius.
     * \param x The center - x coordinate in pixels.
     * \param y The center - y coordinate in pixels.
     * \param radius The radius - in pixels.
     * \param color The color of the circle.
     * \param width The desired width of the line (this is IGNORED in this
     * virtual class)
     */
    virtual void drawCircle(
        int x, int y, int radius,
        const mrpt::img::TColor& color = mrpt::img::TColor(255, 255, 255),
        unsigned int width = 1);

    /** Draws an ellipse representing a given confidence interval of a 2D
     * Gaussian distribution.
     * \param mean_x The x coordinate of the center point of the ellipse.
     * \param mean_y The y coordinate of the center point of the ellipse.
     * \param cov2D A 2x2 covariance matrix.
     * \param confIntervalStds How many "sigmas" for the confidence level (i.e.
     * 2->95%, 3=99.97%,...)
     * \param color The color of the ellipse
     * \param width The desired width of the line (this is IGNORED in this
     * virtual class)
     * \param nEllipsePoints The number of points to generate to approximate
     * the ellipse shape.
     * \exception std::exception On an invalid matrix.
     */
    void ellipseGaussian(
        const mrpt::math::CMatrixFixed<double, 2, 2>& cov2D,
        const double mean_x, const double mean_y, double confIntervalStds = 2,
        const mrpt::img::TColor& color = mrpt::img::TColor(255, 255, 255),
        unsigned int width = 1, int nEllipsePoints = 20);

    /** Draws a set of marks onto the image, given a generic container of
     * entities having just "x" and "y" fields.
     *  The class of FEATURELIST can be, for example,
     * std::vector<mrpt::math::TPoint2D>, std::vector<TPixelCoordsf> or
     * mrpt::vision::CFeatureList
     * \sa drawFeatures
     */
    template <class FEATURELIST>
    void drawFeaturesSimple(
        const FEATURELIST& list, const TColor& color = TColor::red(),
        const int cross_size = 5)
    {
        for (size_t i = 0; i < list.size(); ++i)
        {
            const int x = round(list.getFeatureX(i));
            const int y = round(list.getFeatureY(i));
            drawMark(x, y, color, '+', cross_size);
        }
    }

    /** Draws a set of marks (or scaled circles for features with scale) onto
     * the image, given a generic container of features.
     *  The class of FEATURELIST can be:
     *    - mrpt::vision::CFeatureList
     *    - mrpt::vision::TKeyPointList
     *
     * \sa drawFeaturesSimple
     */
    template <class FEATURELIST>
    void drawFeatures(
        const FEATURELIST& list, const TColor& color = TColor::red(),
        const bool showIDs = false, const bool showResponse = false,
        const bool showScale = false, const char marker = '+')
    {
        for (size_t i = 0; i < list.size(); ++i)
        {
            const int x = round(list.getFeatureX(i));
            const int y = round(list.getFeatureY(i));
            drawMark(x, y, color, marker);
            if (showIDs)
                this->textOut(
                    x, y,
                    format(
                        "%u", static_cast<unsigned int>(list.getFeatureID(i))),
                    TColor::red());
            if (showResponse)
                this->textOut(
                    x, y + 10,
                    format(
                        "R:%u",
                        static_cast<unsigned int>(list.getFeatureResponse(i))),
                    TColor::red());
            if (!list.isPointFeature(i))
            {
                this->drawCircle(x, y, list.getScale(i), TColor::red());
            }
            else if (showScale)
            {
                this->textOut(
                    x, y + 20, format("S:%.01f", list.getScale(i)),
                    TColor::red());
            }
        }
    }
};  // End of class

}  // namespace mrpt::img