How set visible labels with high tilt?

[Александр Тищенко]

Hi. I have app on Android with http tile source. When it render with tilt about 65 the farplane labels sets invisible. How can I fix it? Please help. Thanks.

[Emux]

Do you use VTM OpenGL map library?

What http tile source, does it have vector tiles?

This is how the map tilt works, the remote elements become smaller and smaller
and in the distant horizon the rendering stops.

You can limit the tilt to sane values, like 60-65 degrees.

--
Emux

[Александр Тищенко]

Yes? I use mapsforge-vtm.

I use json tile source like GeojsonTileSource.

I use tilt with 60-65 degrees. I want see house numbers and street's names on more distance. They are visible just more than 50% of display.

среда, 12 мая 2021 г. в 08:58:25 UTC+3, Emux:

[Emux]

This is how map tilt works (see FHD image).

Using very large resolutions (> FHD) or extreme tilts, the horizon cannot be filled.

You can use smaller tilt (50-60) to fill the whole map with labels.

--
Emux

[Александр Тищенко]

And no way to change it?

среда, 12 мая 2021 г. в 10:38:20 UTC+3, Emux:

[Emux]

You can study the code to see if this is possible.

However, this must be optional, as we can not break the library performance by rendering labels over long distances.

--
Emux

[Александр Тищенко]

Thank you. As I understand it is impossible(

/**
* Height and width in pixels
*/
protected float mHeight, mWidth;

public static final float VIEW_DISTANCE = 3.0f;
public static final float VIEW_NEAR = 1;
public static final float VIEW_FAR = 8;
/**
* scale map plane at VIEW_DISTANCE to near plane
*/
public static final float VIEW_SCALE = (VIEW_NEAR / VIEW_DISTANCE) * 0.5f;

среда, 12 мая 2021 г. в 10:59:30 UTC+3, Emux:

[Emux]

If the "final" solves your problem, we can remove them.

But have you tested it with your own VTM clone and it really solves it?

What values have you used?

--
Emux

[Александр Тищенко]

Not yet. I'll write when it will be done.

среда, 12 мая 2021 г. в 11:38:03 UTC+3, Emux:

[Александр Тищенко]

Hi. I tested my solution on 3 devices with different API (23, 25, 30) and different resolution. I've had no any problem.

I've made coefficient in org.oscim.utils.Parameters fot editable it:

/**
* Distance coefficient for drawing labels
*/
public static float DISTANCES_LABELS_COEFFICIENT = 3;

In org.oscim.layers.tile.vector.labeling.LabelPlacement edit function that get mSquareRadius:

float mw = mMap.getWidth();
float mh = mMap.getHeight();

float k = Parameters.DISTANCES_LABELS_COEFFICIENT  * pos.tilt / Viewport.MAX_TILT;
if (k < 0.5) k = 0.5F;

mSquareRadius = (mw * mw + mh * mh) * k;

It let minimise load according tilt's degree

среда, 12 мая 2021 г. в 11:49:14 UTC+3, Александр Тищенко:

[Emux]

If you would like to provide a pull request, we would need:

- A boolean in Parameters, so this is optional and original code remains default

- The COEFFICIENT can be in LabelPlacement
  Or it is the same as Viewport.VIEW_DISTANCE ?

- Better use mMap.viewport().getMaxTilt()

--
Emux

[Александр Тищенко]

- A boolean in Parameters, so this is optional and original code remains default

If you don't want make parameter in Parameters and want take it for all this is not needs. I offer it for editable coefficient.

- The COEFFICIENT can be in LabelPlacement
  Or it is the same as Viewport.VIEW_DISTANCE ?

No, it absolutely different things. Coefficient can be in LabelPlacement

пятница, 14 мая 2021 г. в 17:45:16 UTC+3, Emux:

[Emux]

I cannot understand what you mean.

You propose a core change. This must be optional (via Parameters) to be tested thoroughly and not break user apps.

--
Emux

[Александр Тищенко]

Ok, I understand.

What anything else must I do?

пятница, 14 мая 2021 г. в 18:13:06 UTC+3, Emux:

[Emux]

I described above the process.

You can post a pull request and I will review / improve it before merging.

--
Emux

[Александр Тищенко]

ok, thank you!

пятница, 14 мая 2021 г. в 18:17:17 UTC+3, Emux:

[Александр Тищенко]

I've changed code but can't pushed my new branch

remote: Permission to mapsforge/vtm.git denied to blakfast

пятница, 14 мая 2021 г. в 18:21:05 UTC+3, Александр Тищенко:

[Emux]

Only the administrator can write directly on upstream code.

You need to fork the repository, create a new branch, change the code and create a pull request.

See the GitHub documentation for more details.

--
Emux

[Александр Тищенко]

All done. Thank you for your help!

понедельник, 17 мая 2021 г. в 15:43:42 UTC+3, Emux:

[Emux]

Thanks for the contribution!

--
Emux