Method setMaskColor

src/doc/image.h:45–45

    gfx::Rect bounds() const { return gfx::Rect(0, 0, m_width, m_height); }
    color_t maskColor() const { return m_maskColor; }
    void setMaskColor(color_t c) { m_maskColor = c; }

    virtual int getMemSize() const override;
    int getRowStrideSize() const;