FW: [ft] Generating text metrics on Linux and Windows.

[Tony Smith]

Thanks for the help Werner.

I've analysed the metrics generated by FreeType further with the simple code
below.
FreeType does generate consistent results between the two builds on Windows
and Linux.
The problem lies with my "production" code.

Sorry for the inconvenience, Tony Smith

-----Original Message-----
From: Werner LEMBERG [mailto:address@hidden 
Sent: 24 September 2007 21:41
To: address@hidden
Subject: Re: [ft] Generating text metrics on Linux and Windows.



[Please stay on the list so that other sees your comments too!]

> When I said comparing text metrics on Linux and Windows I meant using 
> the same "FreeType" code.

You say that you get different results for a TrueType font using the same
FreeType code?  Uh, oh, this must not happen, at least not with TrueType
fonts.

> The basis of the code was added to the bottom of my initial query.

Please post the differing results. 

> Would it be more convenient if I had this code in a standard main
> (C) function.

I've adapted your code to be compilable with g++; see below, together with
the result.  I've used times.ttf version 3.00 and plain FreeType 2.3.5.

> I did try some basic tests to compare metrics generated using the 
> Windows FONT technology with ones generated using FreeType.  They did 
> seem to be different but I thought that this would just be too big an 
> ask to get the same values.

They should be the same, provided you don't ask for ClearType rendering.


     Werner


======================================================================


#include <ft2build.h>
#include FT_FREETYPE_H

#include <stdio.h>

int main()
{
  FT_Library library;
  FT_Error error;

  error = FT_Init_FreeType( &library );

  const char *fontFile="times.ttf";
  FT_Face face;
  error = FT_New_Face(library, fontFile, 0, &face);

  double ptSize = 7.992;
  int dpi = 600;
  error = FT_Select_Charmap(face, FT_ENCODING_UNICODE);
  error = FT_Set_Char_Size(face, 0, (FT_F26Dot6)(ptSize * (double)64.0),
dpi, dpi);

  int charMetrics[256];
  for(int ch = 0; ch < 256; ch++)
  {
    int glyph_index = FT_Get_Char_Index(face, ch);
    int load_flags = FT_LOAD_DEFAULT;
    load_flags += FT_LOAD_FORCE_AUTOHINT;
    error = FT_Load_Glyph(face, glyph_index, load_flags);
    charMetrics[ch] = face->glyph->advance.x;
    printf("%d: %d\n", ch, charMetrics[ch]);
  }

  return 0;
}


======================================================================


0: 3328
1: 3328
2: 3328
3: 3328
4: 3328
5: 3328
6: 3328
7: 3328
8: 3328
9: 3328
10: 3328
11: 3328
12: 3328
13: 3328
14: 3328
15: 3328
16: 3328
17: 3328
18: 3328
19: 3328
20: 3328
21: 3328
22: 3328
23: 3328
24: 3328
25: 3328
26: 3328
27: 3328
28: 3328
29: 3328
30: 3328
31: 3328
32: 1088
33: 1344
34: 1664
35: 2112
36: 2112
37: 3520
38: 3264
39: 768
40: 1472
41: 1408
42: 2176
43: 2368
44: 1088
45: 1472
46: 1088
47: 1152
48: 2048
49: 2176
50: 2176
51: 2176
52: 2112
53: 2112
54: 2176
55: 2112
56: 2176
57: 2176
58: 1152
59: 1216
60: 2368
61: 2368
62: 2368
63: 1920
64: 3904
65: 3136
66: 2880
67: 2816
68: 3136
69: 2624
70: 2368
71: 3072
72: 3072
73: 1472
74: 1728
75: 3072
76: 2560
77: 3776
78: 3072
79: 3072
80: 2304
81: 3072
82: 2816
83: 2368
84: 2560
85: 3136
86: 3136
87: 4032
88: 3136
89: 3072
90: 2624
91: 1408
92: 1152
93: 1408
94: 1984
95: 2176
96: 1408
97: 1920
98: 2112
99: 1856
100: 2112
101: 1856
102: 1408
103: 2112
104: 2176
105: 1152
106: 1280
107: 2176
108: 1216
109: 3392
110: 2176
111: 2112
112: 2112
113: 2112
114: 1472
115: 1600
116: 1216
117: 2112
118: 2176
119: 3136
120: 2112
121: 2240
122: 1856
123: 2048
124: 832
125: 2112
126: 2304
127: 3328
128: 3328
129: 3328
130: 3328
131: 3328
132: 3328
133: 3328
134: 3328
135: 3328
136: 3328
137: 3328
138: 3328
139: 3328
140: 3328
141: 3328
142: 3328
143: 3328
144: 3328
145: 3328
146: 3328
147: 3328
148: 3328
149: 3328
150: 3328
151: 3328
152: 3328
153: 3328
154: 3328
155: 3328
156: 3328
157: 3328
158: 3328
159: 3328
160: 1088
161: 1408
162: 2112
163: 2112
164: 2112
165: 2240
166: 832
167: 2112
168: 1408
169: 3200
170: 1216
171: 2112
172: 2432
173: 1472
174: 3200
175: 2176
176: 1664
177: 2368
178: 1280
179: 1280
180: 1408
181: 2432
182: 1920
183: 1088
184: 1472
185: 1280
186: 1344
187: 2112
188: 3200
189: 3200
190: 3200
191: 1920
192: 3136
193: 3136
194: 3136
195: 3136
196: 3136
197: 3136
198: 3776
199: 2816
200: 2624
201: 2624
202: 2624
203: 2624
204: 1472
205: 1472
206: 1472
207: 1472
208: 3072
209: 3072
210: 3072
211: 3072
212: 3072
213: 3072
214: 3072
215: 2432
216: 3072
217: 3136
218: 3136
219: 3136
220: 3136
221: 3072
222: 2368
223: 2112
224: 1920
225: 1920
226: 1920
227: 1920
228: 1920
229: 1920
230: 2816
231: 1856
232: 1856
233: 1856
234: 1856
235: 1856
236: 1152
237: 1152
238: 1152
239: 1216
240: 2112
241: 2176
242: 2112
243: 2112
244: 2112
245: 2112
246: 2112
247: 2368
248: 2112
249: 2112
250: 2112
251: 2112
252: 2112
253: 2240
254: 2112
255: 2240

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