sdltextbox.cpp

游戏开发数据结构-Data.Structures.for.Game.Programmers

// ============================================================================
// Data Structures For Game Programmers
// Ron Penton
// SDLTextBox.cpp
// This is a basic SDLGUI library that I've set up for use with the game demos
// I've used in the book.
// ============================================================================
#include "SDLTextBox.h"
#include <string.h>





// -------------------------------------------------------
// Name:        SDLTextBox::SDLTextBox
// Description: This constructs the text box
// Arguments:   - p_x: x coordinate
//              - p_y: y coordinate
//              - p_w, p_h: the width and height.
//              - p_string: a pointer to the string of
//                          the text box
//              - p_size: the max size of the string.
//              - p_tforecol: the foreground color of the 
//                            text
//              - p_tbackcol: the background color of the
//                            text
//              - p_font: the font of the text.
//              - p_func: the function this calls when
//                        enter is pressed.
// -------------------------------------------------------
SDLTextBox::SDLTextBox( int p_x, int p_y,
                        int p_w, int p_h,
                        char* p_string,
                        int p_size,
                        SDL_Color p_tforecol,
                        SDL_Color p_tbackcol,
                        TTF_Font* p_font,
                        bool p_enabled,
                        void (*p_func)(void) )
{
    m_x = p_x;
    m_y = p_y;
    m_w = p_w;
    m_h = p_h;
    m_string = p_string;
    m_size = p_size;
    m_tforecol = p_tforecol;
    m_tbackcol = p_tbackcol;
    m_font = p_font;
    m_hasFocus = false;
    m_enabled = p_enabled;
    m_func = p_func;

    m_blink = false;
    m_timer = SDL_GetTicks();
}


// ----------------------------------------------------------------
//  Name:           Draw
//  Description:    draws the item on a surface
//  Arguments:      p_dest: the destination surface
//  Return Value:   None
// ----------------------------------------------------------------
void SDLTextBox::Draw( SDL_Surface* p_dest )
{
    // render text
    int blinkx = m_x + 1;

    // if the string has some letters in it
    if( m_string[0] != '\0' )
    {
        // render the text
        SDL_Surface* text = TTF_RenderText_Shaded( m_font, m_string, 
                                                   m_tforecol, m_tbackcol );

        // find out if the text is longer than the width of the box
        if( text->w > m_w )
        {
            // the text is larger than the box, 
            // so render only the right part of the text.
            SDL_Rect sourcerect;
            SDL_Rect destrect;

            sourcerect.w = m_w;
            sourcerect.h = text->h;
            sourcerect.x = text->w - m_w;
            sourcerect.y = 0;
            destrect.w = m_w;
            destrect.h = text->h;
            destrect.x = m_x;
            destrect.y = m_y + ((m_h - text->h) / 2);
            SDL_BlitSurface( text, &sourcerect, p_dest, &destrect );
            blinkx = m_x + m_w - 1;
        }
        else
        {
            // render the whole string
            SDLBlit( text, p_dest, m_x, m_y + ((m_h - text->h) / 2));
            blinkx = m_x + text->w + 1;
        }

        SDL_FreeSurface( text );
    }

    // draw the box.
    if( m_hasFocus == true )
    {
        // red if the box has the focus
        SDLLine( p_dest, m_x, m_y, m_x + m_w, m_y, RED );
        SDLLine( p_dest, m_x, m_y + m_h, m_x + m_w, m_y + m_h, RED );
        SDLLine( p_dest, m_x, m_y, m_x, m_y + m_h, RED );
        SDLLine( p_dest, m_x + m_w, m_y, m_x + m_w, m_y + m_h, RED );
    }
    else
    {
        // grey if the box doesn't have the focus   
        SDLLine( p_dest, m_x, m_y, m_x + m_w, m_y, GREY );
        SDLLine( p_dest, m_x, m_y + m_h, m_x + m_w, m_y + m_h, GREY );
        SDLLine( p_dest, m_x, m_y, m_x, m_y + m_h, GREY );
        SDLLine( p_dest, m_x + m_w, m_y, m_x + m_w, m_y + m_h, GREY );
    }

    // draw blinking cursor.
    if( m_blink == false && m_hasFocus == true )
    {
        SDLLine( p_dest, blinkx, m_y + 2,
                 blinkx, m_y + m_h - 2, BLACK );
    }
    if( SDL_GetTicks() - m_timer > 500 )
    {
        m_timer = SDL_GetTicks();
        m_blink = !m_blink;
    }

}

// ----------------------------------------------------------------
//  Name:           ClickDown
//  Description:    Tells the item that it was clicked on.
//  Arguments:      None
//  Return Value:   None
// ----------------------------------------------------------------
void SDLTextBox::ClickDown()
{
    // do nothing
}


// ----------------------------------------------------------------
//  Name:           ClickUp
//  Description:    Tells the item that it a mouse was released
//                  on this item
//  Arguments:      None
//  Return Value:   None
// ----------------------------------------------------------------
void SDLTextBox::ClickUp()
{
    // do nothing
}

// ----------------------------------------------------------------
//  Name:           IsOver
//  Description:    determines if a set of coordinates is over this
//                  item
//  Arguments:      p_x, p_y: the coordinates
//  Return Value:   true if the coordinates are over this item
// ----------------------------------------------------------------
bool SDLTextBox::IsOver( int p_x, int p_y )
{
    if( p_x >= m_x && p_x < (m_x + m_w) )
    {
        if( p_y >= m_y && p_y < (m_y + m_h) )
        {
            return true;
        }
    }
    return false;
}


// ----------------------------------------------------------------
//  Name:           ResetOnUp
//  Description:    This tells the item to reset itself because
//                  the user unclicked the mouse (only valid
//                  for some items)
//  Arguments:      None
//  Return Value:   None
// ----------------------------------------------------------------
void SDLTextBox::ResetOnUp()
{
    // do nothing
    return;
}

    
// ----------------------------------------------------------------
//  Name:           CanGetFocus
//  Description:    determines if the item can get the focus
//  Arguments:      None
//  Return Value:   true if the item can get the focus
// ----------------------------------------------------------------
bool SDLTextBox::CanGetFocus()
{
    if( m_enabled == true )
        return true;
    return false;
}

// ----------------------------------------------------------------
//  Name:           GetFocus
//  Description:    tells the item to get the focus or not.
//  Arguments:      p_focus: true if the item gets the focus
//  Return Value:   None
// ----------------------------------------------------------------
void SDLTextBox::GetFocus( bool p_focus )
{
    m_hasFocus = p_focus;
}


// ----------------------------------------------------------------
//  Name:           KeyPress
//  Description:    tells the GUI that a key was pressed when this
//                  item was in focus
//  Arguments:      p_key: the that was pressed
//                  p_mod: the keyboard modifier flag (shift, alt, 
//                         control).
//                  p_char: the UNICODE representation of the key
//  Return Value:   None
// ----------------------------------------------------------------
void SDLTextBox::KeyPress( SDLKey p_key, SDLMod p_mod, Uint16 p_char )
{
    int current = strlen( m_string );
    char k = (char)p_char;

    if( p_key == SDLK_DELETE || p_key == SDLK_BACKSPACE )
    {
        m_string[current - 1] = 0;
    }
    else if( p_key == SDLK_RETURN )
    {
        if( m_func != 0 )
        {
            m_func();
        }
    }
    else
    {
        // only accept 'character' keys
        if( p_key >= SDLK_SPACE && p_key <= SDLK_z )
        {
            if( current < m_size )
            {
                m_string[current] = k;
                m_string[current+1] = 0;
            }
        }
    }
}