freetype日记1

freetype日记1

1、对draw_bitmap的理解

slot->bitmap_left、slot->bitmap_top是每块字在笛卡尔最左上角的点

target_height - slot->bitmap_top是转化成LCD上的Y值；

draw_bitmap( &slot->bitmap,
slot->bitmap_left,
target_height - slot->bitmap_top )

代码：

/* example1.c                                                      */
/*                                                                 */
/* This small program shows how to print a rotated string with the */
/* FreeType 2 library.                                             */

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <wchar.h>

#include <ft2build.h>
#include FT_FREETYPE_H
#include FT_GLYPH_H

#define WIDTH   80
#define HEIGHT  80

/* origin is the upper left corner */
unsigned char image[HEIGHT][WIDTH];

/* Replace this function with something useful. */

void
draw_bitmap( FT_Bitmap*  bitmap,
FT_Int      x,
FT_Int      y)
{
FT_Int  i, j, p, q;
FT_Int  x_max = x + bitmap->width;
FT_Int  y_max = y + bitmap->rows;

//printf("x = %d, y = %d\n", x, y);

for ( i = x, p = 0; i < x_max; i++, p++ )
{
for ( j = y, q = 0; j < y_max; j++, q++ )
{
if ( i < 0      || j < 0       ||
i >= WIDTH || j >= HEIGHT )
continue;

image[j][i] |= bitmap->buffer[q * bitmap->width + p];
}
}
}

void
show_image( void )
{
int  i, j;

for ( i = 0; i < HEIGHT; i++ )
{
printf("%02d", i);
for ( j = 0; j < WIDTH; j++ )
putchar( image[i][j] == 0 ? ' '
: image[i][j] < 128 ? '+'
: '*' );
putchar( '\n' );
}
}

int
main( int     argc,
char**  argv )
{
FT_Library    library;
FT_Face       face;

FT_GlyphSlot  slot;
FT_Matrix     matrix;                 /* transformation matrix */
FT_Vector     pen;                    /* untransformed origin  */
FT_Error      error;

char*         filename;
char*         text;

double        angle;
int           target_height;
int           n, num_chars;

//int chinese_str[] = {0x97e6, 0x4e1c, 0x5c71, 0x0067};
//char *str = "韦东山";
wchar_t *chinese_str = L"韦gif";
unsigned int *p = (wchar_t *)chinese_str;
int i;
FT_BBox bbox;
FT_Glyph  glyph;

printf("Uniocde: \n");
for (i = 0; i < wcslen(chinese_str); i++)
{
printf("0x%x ", p[i]);
}
printf("\n");
//return 0;

if ( argc != 2 )
{
fprintf ( stderr, "usage: %s font\n", argv[0] );
exit( 1 );
}

filename      = argv[1];                           /* first argument     */
//text          = argv[2];                           /* second argument    */
//num_chars     = strlen( text );
angle         = ( 0.0 / 360 ) * 3.14159 * 2;      /* use 25 degrees     */
target_height = HEIGHT;

error = FT_Init_FreeType( &library );              /* initialize library */
/* error handling omitted */

error = FT_New_Face( library, argv[1], 0, &face ); /* create face object */
/* error handling omitted */

#if 0
/* use 50pt at 100dpi */
error = FT_Set_Char_Size( face, 50 * 64, 0,
100, 0 );                /* set character size */

/* pixels = 50 /72 * 100 = 69  */
#else
FT_Set_Pixel_Sizes(face, 24, 0);
#endif
/* error handling omitted */

slot = face->glyph;

/* set up matrix */
matrix.xx = (FT_Fixed)( cos( angle ) * 0x10000L );
matrix.xy = (FT_Fixed)(-sin( angle ) * 0x10000L );
matrix.yx = (FT_Fixed)( sin( angle ) * 0x10000L );
matrix.yy = (FT_Fixed)( cos( angle ) * 0x10000L );

/* the pen position in 26.6 cartesian space coordinates; */
/* start at (0,40) relative to the upper left corner  */
pen.x = 0 * 64;
pen.y = ( target_height - 40 ) * 64;

for ( n = 0; n < wcslen(chinese_str); n++ )
{
/* set transformation */
FT_Set_Transform( face, &matrix, &pen );

/* load glyph image into the slot (erase previous one) */
error = FT_Load_Char( face, chinese_str
, FT_LOAD_RENDER );
if ( error )
continue;                 /* ignore errors */

error = FT_Get_Glyph( face->glyph, &glyph );
if (error)
{
printf("FT_Get_Glyph error!\n");
return -1;
}
//从glyph里得到bbox
//FT_GLYPH_BBOX_TRUNCATE 以像素为单位坐标，获得bbox
FT_Glyph_Get_CBox(glyph, FT_GLYPH_BBOX_TRUNCATE, &bbox );

/* now, draw to our target surface (convert position) */
draw_bitmap( &slot->bitmap,
slot->bitmap_left,
target_height - slot->bitmap_top );

printf("Unicode: 0x%x\n", chinese_str
);
printf("origin.x/64 = %d, origin.y/64 = %d\n", pen.x/64, pen.y/64);
printf("xMin = %d, xMax = %d, yMin = %d, yMax = %d\n", bbox.xMin, bbox.xMax, bbox.yMin, bbox.yMax);
printf("slot->advance.x/64 = %d, slot->advance.y/64 = %d\n", slot->advance.x/64, slot->advance.y/64);

/* increment pen position */
pen.x += slot->advance.x;
pen.y += slot->advance.y;
}

show_image();

FT_Done_Face    ( face );
FT_Done_FreeType( library );

return 0;
}

/* EOF */