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fix: black and white is shown as it prints, and right-click prints the picture

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Printing through Elmer found two things. Black and white came out grey
while the preview stayed in colour: 0.2.6.2 only told the driver. And
right-clicking a picture in a lesson and choosing Print printed the whole
page around it, where some pictures cannot be opened on their own at all.

Black and white is now made before the preview. Ghostscript makes a grey
copy, the preview shows it, and CUPS is given that same file, still with
ColorModel=Grayscale so Elmer's PCL 6 driver prints with pxlmono. Measured
first: Ghostscript's own grey of the colour original and of the copy give
the same greys (Elmer's driver is Ghostscript); poppler's do not. It takes
up to 4.4 s for a lesson page of pictures, so it runs in the background
with a minute to finish, is made once and kept, and a failure is said so
and never printed in colour instead. Ghostscript is now a named dependency;
cups-filters already brought it.

Right-click asks the engine's hit test: on a picture or a canvas it offers
Print image and Print page, elsewhere only Print page. The picture comes
from the engine's own copy image — the only one of five ways measured that
worked for a signed-in picture, a hotlink-protected one, a one-time
address, blob:, data:, another site's, a canvas and WebP — and it fetches
nothing, so the teacher's sign-in is not needed again. It goes through the
clipboard, which is kept and put back; measured under KWin with another
program owning it. A picture that never arrives is said so; the page is
not printed in its place. It then gets the 0.2.6.2 picture layout.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
This commit is contained in:
ekklesia
2026-09-26 16:34:38 -05:00
co-authored by Claude Opus 5.5
parent 550c0bf126
commit 594fbd810e
4 changed files with 514 additions and 44 deletions
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@@ -4,7 +4,7 @@ Section: misc
Priority: optional
Architecture: amd64
Maintainer: Ekklesia
Depends: pkexec, polkit-kde-agent-1, plasma-desktop, plasma-workspace, kwin-wayland, plasma-nm, plasma-pa, plasma-widgets-addons, konsole, sddm, dbus-user-session, xwayland, fonts-dejavu, fonts-noto, network-manager, pipewire, pipewire-audio, wireplumber, pulseaudio-utils, cups, cups-client, cups-filters, foomatic-db-compressed-ppds, python3-gi, python3-gi-cairo, gir1.2-gtk-3.0, gir1.2-gtklayershell-0.1, libnotify-bin, curl, gnupg, ca-certificates, python3-paho-mqtt, python3-pyqt6.qtwebengine, python3-pyqt6, libreoffice-impress, libreoffice-core, poppler-utils, fonts-liberation, fonts-liberation-sans-narrow, fonts-croscore, fonts-crosextra-carlito, fonts-crosextra-caladea, fonts-urw-base35, fonts-roboto, fonts-open-sans, fonts-lato, fonts-montserrat, fonts-noto-extra
Depends: pkexec, polkit-kde-agent-1, plasma-desktop, plasma-workspace, kwin-wayland, plasma-nm, plasma-pa, plasma-widgets-addons, konsole, sddm, dbus-user-session, xwayland, fonts-dejavu, fonts-noto, network-manager, pipewire, pipewire-audio, wireplumber, pulseaudio-utils, cups, cups-client, cups-filters, foomatic-db-compressed-ppds, python3-gi, python3-gi-cairo, gir1.2-gtk-3.0, gir1.2-gtklayershell-0.1, libnotify-bin, curl, gnupg, ca-certificates, python3-paho-mqtt, python3-pyqt6.qtwebengine, python3-pyqt6, libreoffice-impress, libreoffice-core, poppler-utils, ghostscript, fonts-liberation, fonts-liberation-sans-narrow, fonts-croscore, fonts-crosextra-carlito, fonts-crosextra-caladea, fonts-urw-base35, fonts-roboto, fonts-open-sans, fonts-lato, fonts-montserrat, fonts-noto-extra
Recommends: vlc
Conflicts: plasma-welcome, plasma-discover, kdeconnect, kup-backup, khelpcenter
Description: Ekklesia managed classroom environment
@@ -48,6 +48,13 @@ Description: Ekklesia managed classroom environment
import costs 0.34s for a ten-slide deck and nothing at all afterwards.
libreoffice-gtk3 is deliberately NOT here: nothing interactive runs.
.
ghostscript is Wonder Ink's black and white. It was already on every
machine, because cups-filters needs it; it is named here because Wonder
Ink now runs it itself, to make the grey copy of a page that the print
preview shows and CUPS is given. Measured: it is the same engine Elmer's
driver prints with, and its grey differs from what Elmer would have
made of the colour page by at most 1 level in 255.
.
The fonts are what a Google Slides export asks for. The metric
compatible families cover the Microsoft names — Liberation for Arial,
Times New Roman and Courier New, Carlito for Calibri, Caladea for