Adds Word Expansion: use of letter spacing for justification

Bump crengine:
- Text: fix occasional BiDi bad word splitting
- Font: fix HB fallback measurement/drawing mismatches
- Font: do not add letter spacing on diacritics
- Text: tunable use of letter spacing for justification
- Text: dont adjust space after initial quotation mark/dash (rework)
- Text: fix possible bad widths after collapsed spaces

xtext.cpp: pick crengine fix with HB fallback
measurement/drawing mismatches

Adds "Word Expansion" to bottom Font size menu, and moved
"Word Spacing" there too, to balance the panels' heights
to 4 items.

.luacheckrc

@@ -106,6 +106,9 @@ read_globals = {
     "DCREREADER_CONFIG_WORD_SPACING_SMALL",
     "DCREREADER_CONFIG_WORD_SPACING_MEDIUM",
     "DCREREADER_CONFIG_WORD_SPACING_LARGE",
+    "DCREREADER_CONFIG_WORD_EXPANSION_NONE",
+    "DCREREADER_CONFIG_WORD_EXPANSION_SOME",
+    "DCREREADER_CONFIG_WORD_EXPANSION_MORE",
     "DMINIBAR_CONTAINER_HEIGHT",
     "DGESDETECT_DISABLE_DOUBLE_TAP",
     "FRONTLIGHT_SENSITIVITY_DECREASE",

base

@@ -1 +1 @@
-Subproject commit 57c848f3630e150321cfb8a975cc905070cb316e
+Subproject commit 87300d3b026b15f2e6a87505efe8261bf406a1d1

defaults.lua

@@ -185,6 +185,13 @@ DCREREADER_CONFIG_WORD_SPACING_SMALL = {75, 50}
 DCREREADER_CONFIG_WORD_SPACING_MEDIUM = {95, 75}
 DCREREADER_CONFIG_WORD_SPACING_LARGE = {100, 90}
 
+-- word expansion, to reduce excessive spacing on justified line
+-- by using letter spacing on the words
+-- value is the max allowed added letter spacing, as a % of the font size
+DCREREADER_CONFIG_WORD_EXPANSION_NONE = 0
+DCREREADER_CONFIG_WORD_EXPANSION_SOME = 5
+DCREREADER_CONFIG_WORD_EXPANSION_MORE = 15
+
 -- crereader progress bar (no longer needed)
 -- 0 for top "full" progress bar
 -- 1 for bottom "mini" progress bar

frontend/apps/reader/modules/readerfont.lua

@@ -125,6 +125,10 @@ function ReaderFont:onReadSettings(config)
         or G_reader_settings:readSetting("copt_word_spacing") or {95, 75}
     self.ui.document:setWordSpacing(self.word_spacing)
 
+    self.word_expansion = config:readSetting("word_expansion")
+        or G_reader_settings:readSetting("copt_word_expansion") or 0
+    self.ui.document:setWordExpansion(self.word_expansion)
+
     self.line_space_percent = config:readSetting("line_space_percent")
             or G_reader_settings:readSetting("copt_line_spacing")
             or DCREREADER_CONFIG_LINE_SPACE_PERCENT_MEDIUM
@@ -239,6 +243,13 @@ function ReaderFont:onSetWordSpacing(values)
     return true
 end
 
+function ReaderFont:onSetWordExpansion(value)
+    self.word_expansion = value
+    self.ui.document:setWordExpansion(value)
+    self.ui:handleEvent(Event:new("UpdatePos"))
+    return true
+end
+
 function ReaderFont:onSetFontGamma(gamma)
     self.gamma_index = gamma
     self.ui.document:setGammaIndex(self.gamma_index)
@@ -259,6 +270,7 @@ function ReaderFont:onSaveSettings()
     self.ui.doc_settings:saveSetting("font_hinting", self.font_hinting)
     self.ui.doc_settings:saveSetting("font_kerning", self.font_kerning)
     self.ui.doc_settings:saveSetting("word_spacing", self.word_spacing)
+    self.ui.doc_settings:saveSetting("word_expansion", self.word_expansion)
     self.ui.doc_settings:saveSetting("line_space_percent", self.line_space_percent)
     self.ui.doc_settings:saveSetting("gamma_index", self.gamma_index)
 end

frontend/document/credocument.lua

@@ -812,6 +812,11 @@ function CreDocument:setWordSpacing(values)
     self._document:setIntProperty("crengine.style.space.condensing.percent", values[2])
 end
 
+function CreDocument:setWordExpansion(value)
+    logger.dbg("CreDocument: set word expansion", value)
+    self._document:setIntProperty("crengine.style.max.added.letter.spacing.percent", value or 0)
+end
+
 function CreDocument:setStyleSheet(new_css_file, appended_css_content )
     logger.dbg("CreDocument: set style sheet:",
         new_css_file and new_css_file or "no file",

frontend/ui/data/creoptions.lua

@@ -300,7 +300,7 @@ Note that your selected font size is not affected by this setting.]]),
             },
             {
                 name = "font_fine_tune",
-                name_text = S.FONTSIZE_FINE_TUNING,
+                name_text = S.FONT_SIZE,
                 toggle = Device:isTouchDevice() and {S.DECREASE, S.INCREASE} or nil,
                 item_text = not Device:isTouchDevice() and {S.DECREASE, S.INCREASE} or nil,
                 more_options = true,
@@ -325,7 +325,63 @@ Note that your selected font size is not affected by this setting.]]),
                     }
                     optionsutil.showValues(configurable, opt, prefix)
                 end,
-            }
+            },
+            {
+                name = "word_spacing",
+                name_text = S.WORD_SPACING,
+                toggle = {S.SMALL, S.MEDIUM, S.LARGE},
+                values = {
+                    DCREREADER_CONFIG_WORD_SPACING_SMALL,
+                    DCREREADER_CONFIG_WORD_SPACING_MEDIUM,
+                    DCREREADER_CONFIG_WORD_SPACING_LARGE,
+                },
+                default_value = DCREREADER_CONFIG_WORD_SPACING_MEDIUM,
+                args = {
+                    DCREREADER_CONFIG_WORD_SPACING_SMALL,
+                    DCREREADER_CONFIG_WORD_SPACING_MEDIUM,
+                    DCREREADER_CONFIG_WORD_SPACING_LARGE,
+                },
+                event = "SetWordSpacing",
+                help_text = _([[Tells the rendering engine how much to scale the width of each 'space' character in the text from its regular width, and how much it can additionally reduce them to make more words fit on a line (100% means no reduction).]]),
+                name_text_hold_callback = optionsutil.showValues,
+                name_text_true_values = true,
+                show_true_value_func = function(val)
+                    return string.format("%d%%, +%d%%", val[1], val[2])
+                end,
+            },
+            {
+                name = "word_expansion",
+                name_text = S.WORD_EXPANSION,
+                more_options = true,
+                more_options_param = {
+                    value_min = 0,
+                    value_max = 20,
+                    value_step = 1,
+                    value_hold_step = 4,
+                    name = "word_expansion",
+                    name_text = _("Allowed word expansion (%)"),
+                    event = "SetWordExpansion",
+                },
+                toggle = {S.NONE, S.SOME, S.MORE},
+                values = {
+                    DCREREADER_CONFIG_WORD_EXPANSION_NONE,
+                    DCREREADER_CONFIG_WORD_EXPANSION_SOME,
+                    DCREREADER_CONFIG_WORD_EXPANSION_MORE,
+                },
+                default_value = DCREREADER_CONFIG_WORD_EXPANSION_NONE,
+                args = {
+                    DCREREADER_CONFIG_WORD_EXPANSION_NONE,
+                    DCREREADER_CONFIG_WORD_EXPANSION_SOME,
+                    DCREREADER_CONFIG_WORD_EXPANSION_MORE,
+                },
+                event = "SetWordExpansion",
+                help_text = _([[On justified lines having too wide spaces, allow distributing the excessive space into words by expanding them with letter spacing. This sets the max allowed letter spacing as a % of the font size.]]),
+                name_text_hold_callback = optionsutil.showValues,
+                name_text_true_values = true,
+                show_true_value_func = function(val)
+                    return string.format("%d%%", val)
+                end,
+            },
         }
     },
     {
@@ -400,29 +456,6 @@ Note that your selected font size is not affected by this setting.]]),
 
 (Font Hinting may need to be adjusted for the best result with either kerning implementation.)]]),
             },
-            {
-                name = "word_spacing",
-                name_text = S.WORD_SPACING,
-                toggle = {S.SMALL, S.MEDIUM, S.LARGE},
-                values = {
-                    DCREREADER_CONFIG_WORD_SPACING_SMALL,
-                    DCREREADER_CONFIG_WORD_SPACING_MEDIUM,
-                    DCREREADER_CONFIG_WORD_SPACING_LARGE,
-                },
-                default_value = DCREREADER_CONFIG_WORD_SPACING_MEDIUM,
-                args = {
-                    DCREREADER_CONFIG_WORD_SPACING_SMALL,
-                    DCREREADER_CONFIG_WORD_SPACING_MEDIUM,
-                    DCREREADER_CONFIG_WORD_SPACING_LARGE,
-                    },
-                event = "SetWordSpacing",
-                help_text = _([[Tells the rendering engine how much to scale the width of each 'space' character in the text from its regular width, and how much it can additionally reduce them to make more words fit on a line (100% means no reduction).]]),
-                name_text_hold_callback = optionsutil.showValues,
-                name_text_true_values = true,
-                show_true_value_func = function(val)
-                    return string.format("%d%%, +%d%%", val[1], val[2])
-                end,
-            }
         }
     },
     {

frontend/ui/data/strings.lua

@@ -17,6 +17,7 @@ S.COLUMNS = _("Columns")
 -- @translators Text alignment. Options given as icons: left, right, center, justify.
 S.TEXT_ALIGN = _("Alignment")
 S.FONTSIZE_FINE_TUNING = _("Fine Tuning")
+S.FONT_SIZE = _("Font Size")
 S.CONTRAST = _("Contrast")
 -- @translators Reflow text.
 S.REFLOW = _("Reflow")
@@ -34,6 +35,7 @@ S.GAMMA = _("Gamma")
 S.FONT_HINT = _("Font Hinting")
 S.FONT_KERNING = _("Font Kerning")
 S.WORD_SPACING = _("Word Spacing")
+S.WORD_EXPANSION = _("Word Expansion")
 S.VIEW_MODE = _("View Mode")
 S.EMBEDDED_STYLE = _("Embedded Style")
 S.EMBEDDED_FONTS = _("Embedded Fonts")
@@ -57,6 +59,8 @@ S.NONE = _("none")
 S.SMALL = _("small")
 S.MEDIUM = _("medium")
 S.LARGE = _("large")
+S.SOME = _("some")
+S.MORE = _("more")
 S.DECREASE = _("decrease")
 S.INCREASE = _("increase")
 S.LIGHTEST = _("lightest")

spec/unit/defaults_spec.lua

@@ -8,24 +8,27 @@ describe("defaults module", function()
 
     it("should load all defaults from defaults.lua", function()
         Defaults:init()
-        assert.is_same(103, #Defaults.defaults_name)
+        assert.is_same(106, #Defaults.defaults_name)
     end)
 
     it("should save changes to defaults.persistent.lua", function()
         local persistent_filename = DataStorage:getDataDir() .. "/defaults.persistent.lua"
         os.remove(persistent_filename)
 
+        -- To see indices and help updating this when new settings are added:
+        -- for i=1, 106 do print(i.." ".. Defaults.defaults_name[i]) end
+
         -- not in persistent but checked in defaults
         Defaults.changed[20] = true
-        Defaults.changed[47] = true
+        Defaults.changed[50] = true
-        Defaults.changed[53] = true
+        Defaults.changed[56] = true
-        Defaults.changed[82] = true
+        Defaults.changed[85] = true
-        Defaults.changed[98] = true  --SEARCH_LIBRARY_PATH = ""
+        Defaults.changed[101] = true  --SEARCH_LIBRARY_PATH = ""
         Defaults:saveSettings()
-        assert.is_same(103, #Defaults.defaults_name)
+        assert.is_same(106, #Defaults.defaults_name)
-        assert.is_same("SEARCH_LIBRARY_PATH", Defaults.defaults_name[98])
+        assert.is_same("SEARCH_LIBRARY_PATH", Defaults.defaults_name[101])
-        assert.is_same("DTAP_ZONE_BACKWARD", Defaults.defaults_name[82])
+        assert.is_same("DTAP_ZONE_BACKWARD", Defaults.defaults_name[85])
-        assert.is_same("DCREREADER_CONFIG_WORD_SPACING_LARGE", Defaults.defaults_name[47])
+        assert.is_same("DCREREADER_CONFIG_WORD_SPACING_LARGE", Defaults.defaults_name[50])
         assert.is_same("DCREREADER_CONFIG_H_MARGIN_SIZES_XXX_LARGE", Defaults.defaults_name[20])
         local fd = io.open(persistent_filename, "r")
         assert.Equals(
@@ -57,15 +60,15 @@ DDOUBLE_TAP_ZONE_PREV_CHAPTER = {
 
         -- in persistent
         Defaults:init()
-        Defaults.changed[53] = true
+        Defaults.changed[56] = true
-        Defaults.defaults_value[53] = {
+        Defaults.defaults_value[56] = {
             y = 0,
             x = 0,
             h = 0.25,
             w = 0.75
         }
-        Defaults.changed[82] = true
+        Defaults.changed[85] = true
-        Defaults.defaults_value[82] = {
+        Defaults.defaults_value[85] = {
             y = 10,
             x = 10.125,
             h = 20.25,
@@ -119,8 +122,8 @@ DHINTCOUNT = 2
 
         -- in persistent
         Defaults:init()
-        Defaults.changed[54] = true
+        Defaults.changed[57] = true
-        Defaults.defaults_value[54] = 1
+        Defaults.defaults_value[57] = 1
         Defaults:saveSettings()
         fd = io.open(persistent_filename)
         assert.Equals(