tcGuiDspDisplay

Introduction

The tcGuiDspDisplay class allows the user to draw, erase, write text and bitmaps on a simple memory mapped display interface. Support is provided for multiple display screens, including virtual screens that are not mapped directly to the hardware. Any of the hardware-mapped pages may be made visible. ScreenXOR, ScreenOR, and ScreenAND functions are provided to combine screens.

The constructor for the tcGuiDspDisplay class takes as arguments the width, height, and bit depth of the screens, and a number of "screens" of the specified size are created at the provided memory addresses. A default font for text display is also required.

The tcGuiDspDisplay class is a re-implementation of the MityDSP::tcDspDisplay class (included in the core library), which has been deprecated. This class provides additional methods and slightly different interfaces in order to support integration with the ggui Graphical User Interface library, a view/widget based graphics library supported by the MityDSP CPU engine.

While raw use of this class is possible, typically this class will be used with a MityDSP::tcGuiFramework class in order to support ggui based human machine interface.

Warning:

- currently, only 16 bit screen depths are tested/supported with the ggui library implementation of this class. This was done primarily to provide efficient drawing and rasterization functions.

See also:

MityDSP::tcGuiDspDisplay Class Reference

guiDspDisplay.h

MityDSP::tcGuiFramework

Example

This is a simple example of tcGuiDspDisplay creation and usage:

 #define NUM_LCD_SCREENS  2
 #define LCD_COMMAND_ADDR 0xA0000800
 #define SCR1_ADDR        0xA0000000
 #define SCR2_ADDR        0xA0000400

 #define SCR_WIDTH  128
 #define SCR_HEIGHT  64
 #define SCR_DEPTH   16

 {
     unsigned char *lcd_screens[NUM_LCD_SCREENS] = { (unsigned char *)SCR1_ADDR,
                                                     (unsigned char *)SCR2_ADDR };
     tcDspFont     *lpNarrowFont;
     tcGuiDspDisplay  *lpLCD;

     // create fonts to use on display
     lpNarrowFont = new tcDspFont(/* see tcDspFont for details */);

     // create the display interface
     lpLCD = new tcGuiDspDisplay(SCR_WIDTH, SCR_HEIGHT, SCR_DEPTH,
                                 NUM_LCD_SCREENS,
                                 (void *)LCD_COMMAND_ADDR,
                                 (void **)lcd_screens, lpNarrowFont);

     tcGuiDspDisplay::screenCoords_t new_pos;

     // make screen_1 visible while we draw on screen_2
     mpLCD->setActiveScreen(tcGuiDspDisplay::screen_1);
     mpLCD->clearScreen(NULL,NULL);
     mpLCD->setVisibleScreen(tcGuiDspDisplay::screen_1);
     mpLCD->setActiveScreen(tcGuiDspDisplay::screen_2);
     mpLCD->clearScreen(NULL,NULL);

     // say hi!
     new_pos = mpLCD->drawText(7,0,"Hello World!");
     new_pos = mpLCD->drawText(new_pos," MityDSP here!");

     // draw a logo bitmap
     tcBitmap bmp (LOGO_WIDTH, LOGO_HEIGHT, 1, Logo);
     mpLCD->drawBitmap(16, 11, bmp);

     // make screen_2 visible, and now draw on screen_1
     mpLCD->setVisibleScreen(screen_2);

     ...
 }