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
|
---
description: Pixelflut emulating teletext aka *Tekst-TV* featuring schedule, and user content *news* section
created: 2024-07-07
---
## Idea
This years BornHack will feature an even cooler Pixelflut setup, which inspired me to make something for it.
An important goal was to have something with a low barrier of entry to interact with it.
My first idea involved a keyboard presented at the Pixelflut setup,
allowing one to type messages to be displayed on screen.
Then later i got the idea to make it Text TV themed, this works well with the nerdy culture, and allows me to add a
schedule, and get user interaction through a "news" section.
### Mock up
### Inspiration
<iframe src="https://www.dr.dk/cgi-bin/fttv1.exe/100" style="border:none;height:490px;width:320px" title="Tekst TV - dr.dk"></iframe>
---
## Renderer coding
### Text rendering in C using pango & cairo
Based on a cairo pixel flut code sample from a fellow hacker, which i could expand to import and image, rather easily,
and render text, which worked, but it was anti aliased, making it look horible in the small format.
Top is gimp mock up text,
bottom is pango cairo rendered text
### Turning off anti aliasing
This was annoying, because `cairo_set_antialias(cr, CAIRO_ANTIALIAS_NONE);` didn't work,
it had to be done in pango context.
[Change font rendering (non-antialiased) with pango - stackoverflow.com](https://stackoverflow.com/questions/16106659/change-font-rendering-non-antialiased-with-pango#answer-73221211)
An answer in this stack overflow question, mentions that:
*"In C you can turn off anti-aliasing when drawing with Pangocairo like this:"*
```c
cairo_font_options_t *options = cairo_font_options_create();
cairo_font_options_set_antialias(options, CAIRO_ANTIALIAS_NONE);
pango_cairo_context_set_font_options(context, options);
cairo_font_options_destroy(options);
```
Next problem then, is getting the context.
I found out how to do this in: [pango examples cairoshape.c - gitlab.com](https://gitlab.gnome.org/GNOME/pango/-/blob/239e030e4f38f0b7b899a8a405437601daf2860d/examples/cairoshape.c#L137)
Using `layout = pango_cairo_create_layout (cr);` and `pango_layout_get_context (layout);`
This means i can now turn off, anti aliasing
Here's a code sample:
```c
cairo_surface_t *surface;
cairo_t *cr;
surface = cairo_image_surface_create_for_data(
f->image, f->format,
f->width, f->height, f->stride);
cr = cairo_create(surface);
//cairo_scale (cr, 2, 2);
//cairo_set_antialias(cr, CAIRO_ANTIALIAS_NONE);
int w, h;
cairo_surface_t *image;
image = cairo_image_surface_create_from_png ("../base.png");
w = cairo_image_surface_get_width (image);
h = cairo_image_surface_get_height (image);
//cairo_translate (cr, 0, 1080 - h);
cairo_set_source_surface (cr, image, 0, 0);
cairo_paint (cr);
// Set up the Pango Cairo context
PangoLayout *layout = pango_cairo_create_layout(cr);
PangoFontDescription *font_desc = pango_font_description_from_string("Monospace 7");
//pango_font_description_set_size(font_desc, 8 * PANGO_SCALE);
pango_layout_set_font_description(layout, font_desc);
pango_font_description_free(font_desc);
// Turn off antialias
PangoContext *pango_context = pango_layout_get_context (layout);
cairo_set_antialias(cr, CAIRO_ANTIALIAS_NONE);
cairo_font_options_t *options = cairo_font_options_create();
cairo_font_options_set_antialias(options, CAIRO_ANTIALIAS_NONE);
pango_cairo_context_set_font_options(pango_context, options);
cairo_font_options_destroy(options);
// Move
cairo_translate (cr, 6, 115);
// Set the text to display
pango_layout_set_text(layout, "Hello World!", -1);
// Render the layout
cairo_set_source_rgb(cr, 1, 1, 1); // Set color to white
pango_cairo_show_layout(cr, layout);
// Clean up
g_object_unref(layout);
cairo_destroy (cr);
cairo_surface_destroy(surface);
```
Which renderes non-anti-aliased text
Again, top is gimp mock up text,
bottom is pango cairo rendered text
|
