1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
|
%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2008-2009. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
%% @doc egd_font
%%
-module(egd_font).
-export([load/1, size/1, glyph/2]).
-include("egd.hrl").
%% Font represenatation in ets table
%% egd_font_table
%%
%% Information:
%% {Key, Description, Size}
%% Key :: {Font :: atom(), information}
%% Description :: any(), Description header from font file
%% Size :: {W :: integer(), H :: integer()}
%%
%% Glyphs:
%% {Key, Translation LSs} where
%% Key :: {Font :: atom(), Code :: integer()}, Code = glyph char code
%% Translation :: {
%% W :: integer(), % BBx width
%% H :: integer(), % BBx height
%% X0 :: integer(), % X start
%% Y0 :: integer(), % Y start
%% Xm :: integer(), % Glyph X move when drawing
%% }
%% LSs :: [[{Xl :: integer(), Xr :: integer()}]]
%% The first list is height (top to bottom), the inner list is the list
%% of line spans for the glyphs horizontal pixels.
%%
%%==========================================================================
%%
%% Interface functions
%%
%%==========================================================================
size(Font) ->
[{_Key, _Description, Size}] = ets:lookup(egd_font_table,{Font,information}),
Size.
glyph(Font, Code) ->
[{_Key, Translation, LSs}] = ets:lookup(egd_font_table,{Font,Code}),
{Translation, LSs}.
load(Filename) ->
{ok, Bin} = file:read_file(Filename),
Font = erlang:binary_to_term(Bin),
load_font_header(Font).
%%==========================================================================
%%
%% Internal functions
%%
%%==========================================================================
%% ETS handler functions
initialize_table() ->
ets:new(egd_font_table, [named_table, ordered_set, public]).
glyph_insert(Font, Code, Translation, LSs) ->
Element = {{Font, Code}, Translation, LSs},
ets:insert(egd_font_table, Element).
font_insert(Font, Description, Dimensions) ->
Element = {{Font, information}, Description, Dimensions},
ets:insert(egd_font_table, Element).
%% Font loader functions
is_font_loaded(Font) ->
try
case ets:lookup(egd_font_table, {Font, information}) of
[] -> false;
_ -> true
end
catch
error:_ ->
initialize_table(),
false
end.
load_font_header({_Type, _Version, Font}) ->
load_font_body(Font).
load_font_body({Key,Desc,W,H,Glyphs,Bitmaps}) ->
case is_font_loaded(Key) of
true -> Key;
false ->
% insert dimensions
font_insert(Key, Desc, {W,H}),
parse_glyphs(Glyphs, Bitmaps, Key),
Key
end.
parse_glyphs([], _ , _Key) -> ok;
parse_glyphs([Glyph|Glyphs], Bs, Key) ->
{Code, Translation, LSs} = parse_glyph(Glyph, Bs),
glyph_insert(Key, Code, Translation, LSs),
parse_glyphs(Glyphs, Bs, Key).
parse_glyph({Code,W,H,X0,Y0,Xm,Offset}, Bitmasks) ->
BytesPerLine = ((W+7) div 8),
NumBytes = BytesPerLine*H,
<<_:Offset/binary,Bitmask:NumBytes/binary,_/binary>> = Bitmasks,
LSs = render_glyph(W,H,X0,Y0,Xm,Bitmask),
{Code, {W,H,X0,Y0,Xm}, LSs}.
render_glyph(W, H, X0, Y0, Xm, Bitmask) ->
render_glyph(W,{0,H},X0,Y0,Xm,Bitmask, []).
render_glyph(_W, {H,H}, _X0, _Y0, _Xm, _Bitmask, Out) -> Out;
render_glyph(W, {Hi,H}, X0, Y0,Xm, Bitmask , LSs) ->
N = ((W+7) div 8),
O = N*Hi,
<<_:O/binary, Submask/binary>> = Bitmask,
LS = render_glyph_horizontal(
Submask, % line glyph bitmask
{down, W - 1}, % loop state
W - 1, % Width
[]), % Linespans
render_glyph(W,{Hi+1,H},X0,Y0,Xm, Bitmask, [LS|LSs]).
render_glyph_horizontal(Value, {Pr, Px}, 0, Spans) ->
Cr = bit_spin(Value, 0),
case {Pr,Cr} of
{up , up } -> % closure of interval since its last
[{0, Px}|Spans];
{up , down} -> % closure of interval
[{1, Px}|Spans];
{down, up } -> % beginning of interval
[{0, 0}|Spans];
{down, down} -> % no change in interval
Spans
end;
render_glyph_horizontal(Value, {Pr, Px}, Cx, Spans) ->
Cr = bit_spin(Value, Cx),
case {Pr,Cr} of
{up , up } -> % no change in interval
render_glyph_horizontal(Value, {Cr, Px}, Cx - 1, Spans);
{up , down} -> % closure of interval
render_glyph_horizontal(Value, {Cr, Cx}, Cx - 1, [{Cx+1,Px}|Spans]);
{down, up } -> % beginning of interval
render_glyph_horizontal(Value, {Cr, Cx}, Cx - 1, Spans);
{down, down} -> % no change in interval
render_glyph_horizontal(Value, {Cr, Px}, Cx - 1, Spans)
end.
bit_spin(Value, Cx) ->
<<_:Cx, Bit:1, _/bits>> = Value,
case Bit of
1 -> up;
0 -> down
end.
|
