[Leonard Hecker (lhecker)]

The original research for a solution all the way back in #11032 contained an
unfortunate flaw. The nearby font loading code was written under the assumption
that Cascadia is missing in the system font collection, leading to our issues.
Adding nearby fonts last into the collection would thus ensure that we use
the system fonts whenever possible, but only have nearby fonts as a fallback.

This didn't work and we figured that we'd have to always prefer loading nearby
fonts over system fonts. #12554 tried to achieve this, but failed to change
the order in which the font set is built. In order to prefer nearby fonts
over system ones, we have to add the system font collection last.

PR Checklist

• Closes Terminal suddenly can't find the font Cascadia Mono #11648
• I work here
• Tests added/passed
• Embarrassment for my incompetence

Validation Steps Performed

• Put Jetbrains Mono into the AppX directory of the Debug build
• Jetbrains Mono shows up in the font selector and is useable

Additionally a more complex mini-test was built:
Using FontForge I've cloned arial.ttf and removed all characters except for
the letter "0". Afterwards I've build a custom font collection the same way
we do it in Terminal, extracted a FontFace named "Arial" and called
IDWriteFont::HasCharacter for the letter "1".
Loading the system font collection first results in TRUE and loading it last
results in FALSE (since my custom arial.ttf doesn't have the letter "1").
This confirms that we need to load the system font collection last.

[Leonard Hecker (lhecker)]

Here's the source code for the "mini-test":

#define UNICODE
#define NOMINMAX
#define WIN32_LEAN_AND_MEAN

#include <Windows.h>
#include <dwrite_3.h>

#include <cstdio>

int main() {
    IDWriteFactory7* factory;
    DWriteCreateFactory(DWRITE_FACTORY_TYPE_SHARED, __uuidof(factory), reinterpret_cast<IUnknown**>(&factory));

    IDWriteFontCollection1* systemFontCollection;
    factory->GetSystemFontCollection(false, &systemFontCollection);

    IDWriteFontSet* systemFontSet;
    systemFontCollection->GetFontSet(&systemFontSet);

    IDWriteFontSetBuilder2* fontSetBuilder;
    factory->CreateFontSetBuilder(&fontSetBuilder);

    // !!!! Change this order around to see the results !!!!
    fontSetBuilder->AddFontFile(L"arial1.ttf");
    fontSetBuilder->AddFontFile(L"arial2.ttf");
    fontSetBuilder->AddFontSet(systemFontSet);

    IDWriteFontSet* fontSet;
    fontSetBuilder->CreateFontSet(&fontSet);

    IDWriteFontCollection1* fontCollection;
    factory->CreateFontCollectionFromFontSet(fontSet, &fontCollection);

    UINT32 index;
    BOOL exists;
    fontCollection->FindFamilyName(L"Arial", &index, &exists);

    IDWriteFontFamily1* fontFamily;
    fontCollection->GetFontFamily(index, &fontFamily);

    IDWriteFont* font;
    fontFamily->GetFirstMatchingFont(DWRITE_FONT_WEIGHT_NORMAL, DWRITE_FONT_STRETCH_NORMAL, DWRITE_FONT_STYLE_NORMAL, &font);

    BOOL has0;
    BOOL has1;
    BOOL has2;
    font->HasCharacter(L'0', &has0);
    font->HasCharacter(L'1', &has1);
    font->HasCharacter(L'2', &has2);

    printf("0: %d\n1: %d\n2: %d\n", has0, has1, has2);

    return 0;
}

[Mike Griese (zadjii-msft)]

[Leonard Hecker (lhecker)]

[Dustin L. Howett (DHowett)]

Critically, this is true on Windows 10, Right?

[Leonard Hecker (lhecker)]

Yep, tested!

[Deleted user (ghost)]

Hello Leonard Hecker (@lhecker)!

Because this pull request has the AutoMerge label, I will be glad to assist with helping to merge this pull request once all check-in policies pass.

p.s. you can customize the way I help with merging this pull request, such as holding this pull request until a specific person approves. Simply @mention me (@msftbot) and give me an instruction to get started! Learn more here.

[Deleted user (ghost)]

🎉Windows Terminal v1.13.1143 has been released which incorporates this pull request.:tada:

Handy links:

• Release Notes
• Store Download

[Deleted user (ghost)]

🎉Windows Terminal Preview v1.14.143 has been released which incorporates this pull request.:tada:

Handy links:

• Release Notes
• Store Download

[kczx3]

Funny enough, I got back from a two week vacation today and the live start menu icon for Terminal showed like it was stuck on a partial upgrade or something. Opened Terminal and it seemed to work (showing version 1.13.11431.0) and correctly used Cascadia Mono, however my Visual Studio Code install could no longer find that font. Additionally, looking in my installed fonts within Windows Settings I could not find either Cascadia Code or Cascadia Mono. Repairing the Terminal install fixed the issue. Sadly, that's what I've had to do with the last two upgrades of Terminal as well. Perhaps 1.14 will finally be the version where that no longer occurs. Who knows, maybe my situation was just a fluke thing.