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#define _GNU_SOURCE
#include <iostream>
#include <cstdarg>
#include <cstdlib>
#include <cstring>
#include <cassert>
#include <unistd.h>
#include "screenbuffer.h"
using namespace std;
static void initTerminal(){
cout<<"\x1B[?1049h" // start alternate screen
"\x1B[2J" // clear screen
"\x1B[H" // move to top left
<<flush;
}
static void deinitTerminal(){
cout<<"\x1B[?1049l" // end alternate screen
<<flush;
}
ScreenBuffer::ScreenBuffer(int W,int H)
:W(W),H(H){
screen=new char[W*H];
prevscreen=new char[W*H];
memset(screen,' ',W*H);
memset(prevscreen,' ',W*H);
initTerminal();
}
ScreenBuffer::~ScreenBuffer(){
delete[] screen;
delete[] prevscreen;
deinitTerminal();
}
void ScreenBuffer::moveto(int x,int y){
assert(x>=0&&x<W&&y>=0&&y<H);
curx=x;
cury=y;
}
void ScreenBuffer::printstr(const char *buf){
int basex=curx;
for(int i=0;buf[i];i++){
if(buf[i]!='\n'){
if(curx==W){
if(cury==H-1){
curx--;
break;
}
curx=basex;
cury++;
}
screen[W*cury+curx]=buf[i];
curx++;
} else {
if(cury==H-1)break;
curx=basex;
}
}
if(curx==W){
if(cury==H-1){
curx--;
} else {
curx=basex;
cury++;
}
}
}
int ScreenBuffer::printf_varargs(const char *format,va_list ap){
char *buf;
int ret=vasprintf(&buf,format,ap);
assert(buf);
printstr(buf);
free(buf);
return ret;
}
__attribute__((format (printf, 2, 3)))
int ScreenBuffer::printf(const char *format,...){
va_list ap;
va_start(ap,format);
int ret=printf_varargs(format,ap);
va_end(ap);
return ret;
}
__attribute__((format (printf, 4, 5)))
int ScreenBuffer::mvprintf(int x,int y,const char *format,...){
moveto(x,y);
va_list ap;
va_start(ap,format);
int ret=printf_varargs(format,ap);
va_end(ap);
return ret;
}
void ScreenBuffer::draw(){
bool changed[W*H];
for(int i=0;i<W*H;i++){
changed[i]=screen[i]!=prevscreen[i];
}
for(int y=0;y<H;y++){
for(int x=1;x<W-1;x++){
changed[W*y+x]|=changed[W*y+x-1]&changed[W*y+x+1];
}
}
bool prepped=false;
for(int y=0;y<H;y++){
bool needtomove=true;
for(int x=0;x<W;x++){
if(!changed[W*y+x]){
needtomove=true;
continue;
}
if(!prepped){
cout<<"\x1B[?25l"; // invisible cursor
prepped=true;
}
if(needtomove){
cout<<"\x1B["<<y+1<<';'<<x+1<<'H';
needtomove=false;
}
cout.put(screen[W*y+x]);
}
}
if(prepped){
cout<<"\x1B[?12;25h" // visible cursor
<<"\x1B["<<H<<';'<<W<<'H' // move past screen
<<flush;
}
memcpy(prevscreen,screen,W*H);
}
void ScreenBuffer::emergencyDeinit(){
static const char *str="\n\x1B[?1049l\x1B[12;25h^C\n";
write(1,str,strlen(str));
}
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