reduced red_ftstring.c from freetype-demo

red_ftstring.c

/****************************************************************************/
/*                                                                          */
/*  The FreeType project -- a free and portable quality TrueType renderer.  */
/*                                                                          */
/*  Copyright (C) 1996-2021 by                                              */
/*  D. Turner, R.Wilhelm, and W. Lemberg                                    */
/*                                                                          */
/*                                                                          */
/*  ftstring.c - simple text string display                                 */
/*                                                                          */
/****************************************************************************/

#include "common.h"
#include "ftcommon.h"
#include "mlgetopt.h"

#include <assert.h>
#include <math.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static const char *Sample[] = {
    /* Custom string if any */
    NULL,
    "Statustext",
    "The quick brown fox jumps over the lazy dog"};

enum { RENDER_MODE_STRING, N_RENDER_MODES };

static struct status_ {
  const char *keys;
  const char *dims;
  const char *device;

  int render_mode;
  unsigned long encoding;
  int res;
  int ptsize; /* current point size */
  int angle;
  const char *text;

  // TODO expand load and draw (100+ LOC each)
  FTDemo_String_Context sc;

  FT_Matrix trans_matrix;
  int font_index;

  const char *header;
  char header_buffer[256];

} status = {"",
            DIM,
            NULL,
            RENDER_MODE_STRING,
            FT_ENCODING_UNICODE,
            72,
            48,
            0,
            NULL,
            {0, 0, 0x8000, 0, NULL, 0, 0},
            {0, 0, 0, 0},
            0,
            NULL,
            {0}};

static FTDemo_Display *display;
static FTDemo_Handle *handle;

/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/****                                                                 ****/
/****                   E V E N T   H A N D L I N G                   ****/
/****                                                                 ****/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/

static void event_text_change(void) {
  static int i = INT_MAX - 1;

  if (++i >= (int)(sizeof(Sample) / sizeof(Sample[0])))
    i = Sample[0] == NULL ? 1 : 0;

  status.text = Sample[i];
}

static int Process_Event(void) {
  grEvent event;
  int ret = 0;
  if (*status.keys)
    event.key = grKEY(*status.keys++);
  else {
    grListenSurface(display->surface, 0, &event);

    if (event.type == gr_event_resize)
      return ret;
  }

  switch (event.key) {
  case grKeyEsc:
  case grKEY('q'):
    ret = 1;
    goto Exit;

  case grKeyTab:
    event_text_change();
    FTDemo_String_Set(handle, status.text);
    goto String;

  default:
    break;
  }

String:
  FTDemo_String_Load(handle, &status.sc); // pretty long method

Exit:
  return ret;
}

static void write_header(FT_Error error_code) {
  FTDemo_Draw_Header(handle, display, status.ptsize, status.res, -1,
                     error_code);

  if (status.header)
    grWriteCellString(display->bitmap, 0, 3 * HEADER_HEIGHT, status.header,
                      display->fore_color);

  grRefreshSurface(display->surface);
}

static FT_Error Render_String(void) {
  FTDemo_String_Draw(handle, display, &status.sc,
                     FT_MulFix(display->bitmap->width, status.sc.center),
                     display->bitmap->rows / 2);

  return FT_Err_Ok;
}

int main(int argc, char **argv) {
  /* Initialize engine */
  handle = FTDemo_New();

  status.ptsize = 20 * 64;
  assert(status.ptsize > 0);

  char* fontfile = "/usr/share/fonts/TTF/DejaVuSerifCondensed.ttf";


  handle->encoding = status.encoding;

  for (; argc > 0; argc--, argv++) {
    error = FTDemo_Install_Font(handle, fontfile, 0, 0); // 140 LOC

    if (error) {
      fprintf(stderr, "failed to install %s", fontfile);
      if (error == FT_Err_Invalid_CharMap_Handle)
        fprintf(stderr, ": missing valid charmap\n");
      else
        fprintf(stderr, "\n");
    }
  }

  if (handle->num_fonts == 0)
    PanicZ("could not open any font file");

  display = FTDemo_Display_New(status.device, status.dims); // 70 LOC

  if (!display)
    PanicZ("could not allocate display surface");

  grSetTitle(display->surface, "FreeType String Viewer - press ? for help");
  FTDemo_Icon(handle, display); //140 LOC

  status.header = NULL;

  event_text_change();

  FTDemo_Set_Current_Font(handle, handle->fonts[status.font_index]); // 40 LOC
  FTDemo_Set_Current_Charsize(handle, status.ptsize, status.res); // 40 LOC

  FTDemo_String_Set(handle, status.text); // 30 LOC
  FTDemo_String_Load(handle, &status.sc); // 100 LOC

  do {
    FTDemo_Display_Clear(display);

    switch (status.render_mode) {
    case RENDER_MODE_STRING:
      error = Render_String();
      break;
    }

    write_header(error);

    status.header = 0;
  } while (!Process_Event());

  printf("Execution completed successfully.\n");

  FTDemo_Display_Done(display); // 10 LOC
  FTDemo_Done(handle); // 30 LOC but cleanup methods for all allocated objecst
  exit(0); /* for safety reasons */

  /* return 0; */ /* never reached */
}

/* End */