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[Devel] Re: [Freetype] SImple example request
From: |
Werner LEMBERG |
Subject: |
[Devel] Re: [Freetype] SImple example request |
Date: |
Tue, 21 Oct 2003 08:43:11 +0200 (CEST) |
> One thing that confuses me a little in the tutorial's example is that
> it says 'start at (300,200)'. Yet if I blindly change this number,
> hoping that it will let me specify the starting point of the text
> string in the image, I get very different results for the y coordinate.
> It was this that kept me bogged down while I worked through it.
In example1, the origin is the upper left corner, while the pen
position uses the lower left corner as its origin. Below is the
updated example (with slight improvements to avoid cut-off glyphs).
Please check whether it is now easier to understand.
> PS: I've replied offlist, is that what is the norm here? At least
> that's how Mailman is configured.
I don't think so. If I hit the `Reply' key, I get both addresses.
Werner
======================================================================
/* 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 <ft2build.h>
#include FT_FREETYPE_H
#define WIDTH 640
#define HEIGHT 480
/* 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;
for ( i = x, p = 0; i < x_max; i++, p++ )
{
for ( j = y, q = 0; j < y_max; j++, q++ )
{
if ( 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++ )
{
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_UInt glyph_index;
FT_Vector pen; /* untransformed origin */
FT_Error error;
char* filename;
char* text;
double angle;
int target_height;
int n, num_chars;
filename = argv[1]; /* first argument */
text = argv[2]; /* second argument */
num_chars = strlen( text );
angle = ( 25.0 / 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 */
/* use 50pt at 100dpi */
error = FT_Set_Char_Size( face, 50 * 64, 0,
100, 0 ); /* set character size */
/* 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 (300,200) relative to the upper left corner */
pen.x = 300 * 64;
pen.y = ( target_height - 200 ) * 64;
for ( n = 0; n < num_chars; n++ )
{
/* set transformation */
FT_Set_Transform( face, &matrix, &pen );
/* load glyph image into the slot (erase previous one) */
error = FT_Load_Char( face, text[n], FT_LOAD_RENDER );
if ( error )
continue; /* ignore errors */
/* now, draw to our target surface (convert position) */
draw_bitmap( &slot->bitmap,
slot->bitmap_left,
target_height - slot->bitmap_top );
/* 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 */
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