Closed Bug 306665 Opened 19 years ago Closed 19 years ago

displayed font size completely wrong - 10 pt on a 110 dpi display is 7 pixel high, instead of 15 pixels

Categories

(Core :: Layout: Text and Fonts, defect)

Product:
Core
Component:
Layout: Text and Fonts
Platform:
x86
Linux
Type:
defect
Priority:
Not set
Severity:
major

Tracking

()

Status:
RESOLVED INVALID

People

(Reporter: bugzilla, Unassigned)

Details

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8b3) Gecko/20050716 Debian/1.0.99+deerpark-alpha2-1 Firefox/1.0+
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8b3) Gecko/20050716 Debian/1.0.99+deerpark-alpha2-1 Firefox/1.0+

This is a Debian GNU/Linux sid system with fontconfig as the font system, and
DejaVu TrueType fonts as the used fonts.

The display is a SiliconGraphics SGI 1600SW LCD TFT panel, which has a
resolution 1600 x 1024 pixels, and display size 369.6 x 236.5 mm, so the
resolution is 110.0 dpi, pixel size 231.0 um = 0.6547 pt (PostScript points, 1
pt = 1/72 in).

I have set the correct resolution in /etc/X11/xdm/Xservers like this:
:0 local /usr/X11R6/bin/X vt7 -dpi 110 -nolisten tcp

I am using Xorg.

The display size is also set in /etc/X11/xorg.conf like this:

Section "Modes"
        Identifier "SGI 1600SW"
        Modeline "1600x1024d32" 103.125 1600 1600 1656 1664 1024 1024 1029 1030
HSkew 7 +Hsync +Vsync
EndSection

Section "Device"
        Identifier      "Number 9 Computer Company Revolution 4"
        Driver          "i128"
        Option          "FlatPanel" "True"
EndSection

Section "Monitor"
        Gamma        1.0 0.5 1.0
        Identifier   "SGI1600SW"
        VendorName   "SGI"
        ModelName    "1600SW"
        UseModes     "SGI 1600SW"
        HorizSync    30-96
        VertRefresh  48-160
        Option       "DPMS"
        DisplaySize  369.6 236.5
EndSection

Section "Screen"
        Identifier      "Default Screen"
        Device          "Number 9 Computer Company Revolution 4"
        Monitor         "SGI1600SW"
        DefaultDepth 24
        SubSection "Display"
                Depth     24
                Modes "1600x1024d32"
        EndSubSection
EndSection

Section "ServerLayout"
        Identifier      "Default Layout"
        Screen          "Default Screen"
        InputDevice     "Generic Keyboard"
        InputDevice     "Configured Mouse"
EndSection

xdpyinfo shows the correct data:

jaworz:~$ xdpyinfo | egrep "resolution|dimensions"
  dimensions:    1600x1024 pixels (369x236 millimeters)
  resolution:    110x110 dots per inch
jaworz:~$

Additionally I have explicitly set the resolution in Firefox:

user_pref("browser.display.screen_resolution", 110);

In Firefox I have set the font size like this:

jaworz:~$ cat /home/miernik/.mozilla/firefox/qza4wx1i.default/prefs.js | grep
size | grep western
user_pref("font.minimum-size.x-western", 10);
user_pref("font.size.fixed.x-western", 10);
user_pref("font.size.variable.x-western", 10);
jaworz:~$

That 10 I assume is in PostScript points, and as I told above, 1 pixel on my
screen is 0.6547 PostScript points, so 10 PostScript points is:

10 / 0.6547 = 15.27

That means that the default font size height (as I assume defined by the height
of the letter H) on my screen should be 15 pixels.

However on my screen the default font (on pages where no CSS is used, and no
font is defined anywhere on the page - I checked many pages, including directory
listings of files on local hard disk), and the height of the letter H is 7 pixels.

Reproducible: Always

Actual Results:  
On a 110 dpi display a 10 pt font is 7 pixels high (measured as the height of
the letter H).

Expected Results:  
The letter H should be 15 pixels high.

My complete prefs.js:

# Mozilla User Preferences

/* Do not edit this file.
 *
 * If you make changes to this file while the application is running,
 * the changes will be overwritten when the application exits.
 *
 * To make a manual change to preferences, you can visit the URL about:config
 * For more information, see http://www.mozilla.org/unix/customizing.html#prefs
 */

user_pref("accessibility.typeaheadfind", true);
user_pref("accessibility.typeaheadfind.flashBar", 0);
user_pref("accessibility.typeaheadfind.linksonly", true);
user_pref("accessibility.warn_on_browsewithcaret", false);
user_pref("browser.blink_allowed", false);
user_pref("browser.cache.disk.enable", false);
user_pref("browser.display.focus_ring_on_anything", true);
user_pref("browser.display.focus_ring_width", 2);
user_pref("browser.display.screen_resolution", 110);
user_pref("browser.display.use_document_fonts", 0);
user_pref("browser.display.use_focus_colors", true);
user_pref("browser.download.dir", "/var/tmp");
user_pref("browser.download.manager.closeWhenDone", true);
user_pref("browser.download.useDownloadDir", false);
user_pref("browser.enable_automatic_image_resizing", false);
user_pref("browser.jsannoyances.disabled", true);
user_pref("browser.link.open_newwindow", 3);
user_pref("browser.preferences.advanced.selectedTabIndex", 0);
user_pref("browser.preferences.lastpanel", 0);
user_pref("browser.preferences.privacy.selectedTabIndex", 2);
user_pref("browser.search.selectedEngine", "Google");
user_pref("browser.startup.homepage_override.mstone", "rv:1.8b3");
user_pref("browser.tabs.autoHide", false);
user_pref("browser.tabs.warnOnClose", false);
user_pref("dom.disable_window_flip", true);
user_pref("dom.disable_window_move_resize", true);
user_pref("dom.event.contextmenu.enabled", false);
user_pref("extensions.disabledObsolete", true);
user_pref("extensions.lastAppVersion", "1.0");
user_pref("font.default.el", "sans-serif");
user_pref("font.default.null", "sans-serif");
user_pref("font.default.th", "sans-serif");
user_pref("font.default.tr", "sans-serif");
user_pref("font.default.x-baltic", "sans-serif");
user_pref("font.default.x-central-euro", "sans-serif");
user_pref("font.default.x-cyrillic", "sans-serif");
user_pref("font.default.x-devanagari", "sans-serif");
user_pref("font.default.x-tamil", "sans-serif");
user_pref("font.default.x-unicode", "sans-serif");
user_pref("font.default.x-user-def", "sans-serif");
user_pref("font.default.x-western", "sans-serif");
user_pref("font.minimum-size.ar", 10);
user_pref("font.minimum-size.el", 10);
user_pref("font.minimum-size.he", 10);
user_pref("font.minimum-size.ja", 10);
user_pref("font.minimum-size.ko", 10);
user_pref("font.minimum-size.null", 10);
user_pref("font.minimum-size.th", 10);
user_pref("font.minimum-size.tr", 10);
user_pref("font.minimum-size.x-baltic", 10);
user_pref("font.minimum-size.x-central-euro", 10);
user_pref("font.minimum-size.x-cyrillic", 10);
user_pref("font.minimum-size.x-devanagari", 10);
user_pref("font.minimum-size.x-tamil", 10);
user_pref("font.minimum-size.x-unicode", 10);
user_pref("font.minimum-size.x-user-def", 10);
user_pref("font.minimum-size.x-western", 10);
user_pref("font.minimum-size.zh-CN", 10);
user_pref("font.minimum-size.zh-HK", 10);
user_pref("font.minimum-size.zh-TW", 10);
user_pref("font.name.monospace.ar", "DejaVu Sans Mono");
user_pref("font.name.monospace.el", "DejaVu Sans Mono");
user_pref("font.name.monospace.he", "DejaVu Sans Mono");
user_pref("font.name.monospace.ja", "DejaVu Sans Mono");
user_pref("font.name.monospace.ko", "DejaVu Sans Mono");
user_pref("font.name.monospace.null", "DejaVu Sans Mono");
user_pref("font.name.monospace.th", "DejaVu Sans Mono");
user_pref("font.name.monospace.tr", "DejaVu Sans Mono");
user_pref("font.name.monospace.x-baltic", "DejaVu Sans Mono");
user_pref("font.name.monospace.x-central-euro", "DejaVu Sans Mono");
user_pref("font.name.monospace.x-cyrillic", "DejaVu Sans Mono");
user_pref("font.name.monospace.x-devanagari", "DejaVu Sans Mono");
user_pref("font.name.monospace.x-tamil", "DejaVu Sans Mono");
user_pref("font.name.monospace.x-unicode", "DejaVu Sans Mono");
user_pref("font.name.monospace.x-user-def", "DejaVu Sans Mono");
user_pref("font.name.monospace.x-western", "DejaVu Sans Mono");
user_pref("font.name.monospace.zh-CN", "DejaVu Sans Mono");
user_pref("font.name.monospace.zh-HK", "DejaVu Sans Mono");
user_pref("font.name.monospace.zh-TW", "DejaVu Sans Mono");
user_pref("font.name.sans-serif.ar", "DejaVu Sans");
user_pref("font.name.sans-serif.el", "DejaVu Sans");
user_pref("font.name.sans-serif.he", "DejaVu Sans");
user_pref("font.name.sans-serif.ja", "DejaVu Sans");
user_pref("font.name.sans-serif.ko", "DejaVu Sans");
user_pref("font.name.sans-serif.null", "DejaVu Sans");
user_pref("font.name.sans-serif.th", "DejaVu Sans");
user_pref("font.name.sans-serif.tr", "DejaVu Sans");
user_pref("font.name.sans-serif.x-baltic", "DejaVu Sans");
user_pref("font.name.sans-serif.x-central-euro", "DejaVu Sans");
user_pref("font.name.sans-serif.x-cyrillic", "DejaVu Sans");
user_pref("font.name.sans-serif.x-devanagari", "DejaVu Sans");
user_pref("font.name.sans-serif.x-tamil", "DejaVu Sans");
user_pref("font.name.sans-serif.x-unicode", "DejaVu Sans");
user_pref("font.name.sans-serif.x-user-def", "DejaVu Sans");
user_pref("font.name.sans-serif.x-western", "DejaVu Sans");
user_pref("font.name.sans-serif.zh-CN", "DejaVu Sans");
user_pref("font.name.sans-serif.zh-HK", "DejaVu Sans");
user_pref("font.name.sans-serif.zh-TW", "DejaVu Sans");
user_pref("font.name.serif.ar", "DejaVu Serif");
user_pref("font.name.serif.el", "DejaVu Serif");
user_pref("font.name.serif.he", "DejaVu Serif");
user_pref("font.name.serif.ja", "DejaVu Serif");
user_pref("font.name.serif.ko", "DejaVu Serif");
user_pref("font.name.serif.null", "DejaVu Serif");
user_pref("font.name.serif.th", "DejaVu Serif");
user_pref("font.name.serif.tr", "DejaVu Serif");
user_pref("font.name.serif.x-baltic", "DejaVu Serif");
user_pref("font.name.serif.x-central-euro", "DejaVu Serif");
user_pref("font.name.serif.x-cyrillic", "DejaVu Serif");
user_pref("font.name.serif.x-devanagari", "DejaVu Serif");
user_pref("font.name.serif.x-tamil", "DejaVu Serif");
user_pref("font.name.serif.x-unicode", "DejaVu Serif");
user_pref("font.name.serif.x-user-def", "DejaVu Serif");
user_pref("font.name.serif.x-western", "DejaVu Serif");
user_pref("font.name.serif.zh-CN", "DejaVu Serif");
user_pref("font.name.serif.zh-HK", "DejaVu Serif");
user_pref("font.name.serif.zh-TW", "DejaVu Serif");
user_pref("font.size.fixed.ar", 10);
user_pref("font.size.fixed.el", 10);
user_pref("font.size.fixed.he", 10);
user_pref("font.size.fixed.ja", 10);
user_pref("font.size.fixed.ko", 10);
user_pref("font.size.fixed.null", 10);
user_pref("font.size.fixed.th", 10);
user_pref("font.size.fixed.tr", 10);
user_pref("font.size.fixed.x-baltic", 10);
user_pref("font.size.fixed.x-central-euro", 10);
user_pref("font.size.fixed.x-cyrillic", 10);
user_pref("font.size.fixed.x-devanagari", 10);
user_pref("font.size.fixed.x-tamil", 10);
user_pref("font.size.fixed.x-unicode", 10);
user_pref("font.size.fixed.x-user-def", 10);
user_pref("font.size.fixed.x-western", 10);
user_pref("font.size.fixed.zh-CN", 10);
user_pref("font.size.fixed.zh-HK", 10);
user_pref("font.size.fixed.zh-TW", 10);
user_pref("font.size.variable.ar", 10);
user_pref("font.size.variable.el", 10);
user_pref("font.size.variable.he", 10);
user_pref("font.size.variable.ja", 10);
user_pref("font.size.variable.ko", 10);
user_pref("font.size.variable.null", 10);
user_pref("font.size.variable.th", 10);
user_pref("font.size.variable.tr", 10);
user_pref("font.size.variable.x-baltic", 10);
user_pref("font.size.variable.x-central-euro", 10);
user_pref("font.size.variable.x-cyrillic", 10);
user_pref("font.size.variable.x-devanagari", 10);
user_pref("font.size.variable.x-tamil", 10);
user_pref("font.size.variable.x-unicode", 10);
user_pref("font.size.variable.x-user-def", 10);
user_pref("font.size.variable.x-western", 10);
user_pref("font.size.variable.zh-CN", 10);
user_pref("font.size.variable.zh-HK", 10);
user_pref("font.size.variable.zh-TW", 10);
user_pref("image.animation_mode", "none");
user_pref("intl.charset.default", "UTF-8");
user_pref("intl.charsetmenu.browser.cache", "us-ascii, UTF-8, ISO-8859-1,
ISO-8859-2, ISO-88510-2");
user_pref("network.cookie.prefsMigrated", true);
user_pref("network.dns.disableIPv6", true);
user_pref("network.http.pipelining", true);
user_pref("network.http.pipelining.maxrequests", 8);
user_pref("network.proxy.http", "1012.168.2.3");
user_pref("network.proxy.http_port", 8080);
user_pref("nglayout.initialpaint.delay", 2000);
user_pref("pref.downloads.disable_button.edit_actions", false);
user_pref("pref.privacy.disable_button.clear_cache", false);
user_pref("pref.privacy.disable_button.clear_formdata", false);
user_pref("pref.privacy.disable_button.clear_history", false);
user_pref("pref.privacy.disable_button.view_passwords", false);
user_pref("privacy.popups.showBrowserMessage", false);
user_pref("security.enable_java", false);
user_pref("security.warn_entering_secure", false);
user_pref("security.warn_leaving_secure", false);
user_pref("security.warn_submit_insecure", false);
user_pref("security.warn_viewing_mixed", false);
user_pref("ui.caretBlinkTime", 0);
user_pref("xpinstall.whitelist.add", "");
user_pref("xpinstall.whitelist.add.103", "");
> That 10 I assume is in PostScript points

but it's in pixels...
Really pixels? 
Is that documented somewhere?
Anyway if so, it should be clearly documented somewhere in the Preferences
dialog, that the numbers mean pixels not points. For me it's somehow natural
that they mean points. 

OTOH, its still wrong, the font which is numbered "10" is 7 pixel high here.
(In reply to comment #2)
> Really pixels? 
> Is that documented somewhere?

The mozilla suite/seamonkey dialog clearly labels the size column "Size (pixels)"...

> OTOH, its still wrong, the font which is numbered "10" is 7 pixel high here.

I don't know why that is...
Component: General → Layout: Fonts and Text
Product: Firefox → Core
QA Contact: general → layout.fonts-and-text
Version: unspecified → Trunk
Status: UNCONFIRMED → NEW
Ever confirmed: true
(In reply to comment #2)
> OTOH, its still wrong, the font which is numbered "10" is 7 pixel high here.

The "height of the letter H" is not the entire height of the font -- there are 
pixels below the baseline, on the descenders, that are included in that height, 
and in many fonts there is bit of room above the top of the capital letters as 
well.
This is invalid -- a 10px font can perfectly well have a 7px-tall letter 'H'.
Status: NEW → RESOLVED
Closed: 19 years ago
Resolution: --- → INVALID
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