Pixi.js: Quality of Text and bitmapText

[Bouh]

Expected Behavior

Text and BitmapText should be visually equal to a Sprite with the same text and same styles.

Current Behavior

The bitmapText and Text are not equal, and not equal to an Sprite with the same text and style.

• Black: The image from photoshop with the same default settings found in PIXI.TextStyle ( except font size, see the settings bellow)
• Red : BitmapText using bitmapFont
• White: Text

Steps to Reproduce

https://jsfiddle.net/Bouh/avogx4n1/2/

Environment

• pixi.js version: dev branch and 5.3.3
• Browser & Version: Chrome 85
• OS & Version: w10
• Running Example: https://jsfiddle.net/Bouh/avogx4n1/2/

[bigtimebuddy]

BitmapFont.from does not support kerning where Text does. This is a known limitation of using BitmapText & BitmapFont.from.

[Bouh]

Ok for kerning on x-axis.
What about the lineHeight or the visible offset on y-axis?

[bigtimebuddy]

BitmapText and Text use different layout methods and are not expected to perfectly line-up in the way you demonstrate. Photoshop also uses a different rasterizing method, so this is not a given.

[Silver-Streak]

@bigtimebuddy Just to confirm, using bitmap font to generate a bitmap text object at 16 px, then scaling up, it looks like this:

But an image made in an editor, then loaded as a texture/sprite, with the exact same font size (16 px) and scaling, looks like this:

The Bitmap text is much blurrier than the png loaded as a sprite.

Is that expected behavior?

[bigtimebuddy]

Can you please provide an example that we can look at rather than just screenshots?

[Silver-Streak]

@Bouh Would you be able to provide your example builds with the example project I had?

I'm not sure if this will be helpful to the team here otherwise.

Here's my exported code, though.

app.zip

Here's the source PNG File being used.

(Transparent background, so you might need to click the space above if it looks empty)

[Silver-Streak]

Sorry, this is where we get a bit past my personal knowledge. @Bouh if you could pull that info out, it'd be greatly appreciated.

[Bouh]

I have been searching for the origin of this problem for months, I have no conclusions to draw from the research I have been able to do unfortunately :/

I don't even know if it's because of PIXI or GDevelop.

Providing a codesandbox environment that replicates GDevelop is too complex for me.
The trick is that this blurring effect is that on text, the sprites are correct, and there is no difference in the implementation of rendering with objects in GDevelop.

I would understand that since it is not proven that this problem affects PIXI, you won't want to get more involved than that.

I can't tell which element is wrong, I would isolate the problem or understand it I would be happy to provide a test link, but i can't.

I call on others with more knowledge to provide their point of view.

(However this issue was for the visual different result of text, now we're wandering on another one, it's a bit off topic.)

(Thx @bigtimebuddy for the current PR of improvement on kerning! )

[Silver-Streak]

@4ian Do you know if you'd be able to point out the code generation needed to show the differences between the objects from the export (or any export from the test build)?

Bouh and I are both a bit past our element.

[4ian]

The way we use Pixi.js in GDevelop has nothing special by itself, so if there is this issue of blurry bitmap font, we should be able to make a JS fiddle with Pixi where we demonstrate the issue :)
@Bouh: let's make a simple example with Pixi.js where we use PIXI.BitmapText, with the same font as the one you used in your example @Silver-Streak
Starting from this, we'll investigate why the font is not blurry in the JS Fiddle and why it's blurry in GDevelop: does it happen when resizing the canvas? Is there some CSS styling on the canvas? Is there a resolution parameter somewhere when we initialize the renderer? Is the way the font is loaded different, etc...

If you can start making a JSFiddle/Codepen with a bitmaptext, using the same font, font size, this can help me then adapting it until we find why it's getting blurry. (In the meantime we can either close this issue as we don't have a proven bug with a reproduction case, but we can continue the discussion here).

[themoonrat]

Tried using roundPixels on the bitmap text object?

[Bouh]

Tried using roundPixels on the bitmap text object?

Yes already tried :)

Here a JSFiddle with the basic stuff, bitmapText and the font used by silver.
There is also some functions for resize the canvas.

[bigtimebuddy]

If you're scaling with a pixel-looking font, we should probably add a scaleMode option for the BaseTextures so you can set it to nearest instead of linear.

[Bouh]

I have in the past tested these settings with max and low value, there is no influence on the blur.

PIXI.settings.ROUND_PIXELS
PIXI.settings.SCALE_MODE
PIXI.settings.PRECISION_FRAGMENT
PIXI.settings.MIPMAP_TEXTURES
PIXI.settings.ANISOTROPIC_LEVEL

Updated JSFiddle with scaleMode

EDIT: Here a new sandbox with blurry text in some case _almost_ similar to GD.
The code sandbox.
The result in live fullscreen

[bigtimebuddy]

That example is complicated, let's simplify it more without Pixi:
https://jsfiddle.net/bigtimebuddy/sc8pgL07/

Inherently, rendering text on canvas without antialias & fillText is not possible (unless someone figured this out). If you need a pixel-looking font, you should _probably_ use a bitmap-font generation tool (e.g. bmGlyph) which probably has more options or there are some approaches where you scale render it at a large size and scale down.

Related: https://www.html5gamedevs.com/topic/23136-how-to-disable-font-antialiasing/

The best I could do it by picking the right sizes plus nearest scaleMode. But it's not perfect.
https://jsfiddle.net/bigtimebuddy/wmkxsgcq/

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