downb.c

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/*****************************************************************************
 * ugBASIC - an isomorphic BASIC language compiler for retrocomputers        *
 *****************************************************************************
 * Copyright 2021-2026 Marco Spedaletti (asimov@mclink.it)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
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 * Unless required by applicable law or agreed to in writing, software
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
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 *----------------------------------------------------------------------------
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 * (la "Licenza"); è proibito usare questo file se non in conformità alla
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 * Se non richiesto dalla legislazione vigente o concordato per iscritto,
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/****************************************************************************
 * INCLUDE SECTION 
 ****************************************************************************/
 
#include "../../ugbc.h"
 
/****************************************************************************
 * CODE SECTION 
 ****************************************************************************/

/* <usermanual>
@keyword DOWNB
 
@english
 
''DOWNB'' allows the programmer to scroll down a section of the text screen from ''x,y''
with the ''width'' and the ''height'', including the colors, line by line. 
The new lines inserted are filled in the upper line with a "blank" character. 
 
Note that this command uses console #3 to store the current console values, in order to 
restore them after scrolling. So it cannot be used by the program.
 
@italian
 
''DOWNBN'' consente al programmatore di scorrere verso il basso una sezione dello schermo 
di testo da ''x,y'' con la ''width'' e l''height'', inclusi i colori, riga per riga. 
Le nuove righe inserite vengono riempite nella riga superiore con un carattere "vuoto".
 
Da notare che questo comando utilizza la console nr. 3 per stoccare i valori della 
console attuale, al fine di ripristinarli al termine dello scorrimento. Quindi non 
può essere utilizzato dal programma.
 
@syntax DOWNB y, x, width, height
 
@example DOWNB 1, 1, 10, 10
 
@seeAlso DOWNW
 
@target all
</usermanual> */
void downb( Environment * _environment, char * _line, char * _column, char * _width, char * _height ) {
 
    Variable * column = variable_retrieve_or_define( _environment, _column, VT_BYTE, 0 );
    Variable * line = variable_retrieve_or_define( _environment, _line, VT_BYTE, 0 );
    Variable * width = variable_retrieve_or_define( _environment, _width, VT_BYTE, _environment->screenTilesWidth );
    Variable * height = variable_retrieve_or_define( _environment, _height, VT_BYTE, _environment->screenTilesHeight  );
 
    Variable * x2 = variable_add( _environment, column->name, width->name );
    Variable * y2 = variable_add( _environment, line->name, height->name );
 
    variable_decrement( _environment, x2->name );
    variable_decrement( _environment, y2->name );
    
    int previous = _environment->activeConsole.id;
    console_save( _environment, 3 );
    console_vars( _environment, _column, _line, x2->name, y2->name );
    text_vscroll_screen( _environment, 1, 0 );
    console_restore( _environment, previous );
 
}