1 files changed, 249 insertions, 0 deletions
diff --git a/src/ui/modifiers.h b/src/ui/modifiers.h
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+++ b/src/ui/modifiers.h
@@ -0,0 +1,249 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#ifndef SEEN_SP_MODIFIERS_H
+#define SEEN_SP_MODIFIERS_H
+/*
+ *  Copyright (C) 2020 Martin Owens <doctormo@gmail.com>
+
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include <cstring>
+#include <cstdarg>
+#include <string>
+#include <vector>
+#include <map>
+
+#include <gdk/gdk.h>
+
+#include "message-context.h"
+
+namespace Inkscape {
+namespace Modifiers {
+
+using KeyMask = int;
+using Trigger = int;
+
+enum Key : KeyMask {
+    NEVER = -2, // Never happen, switch off
+    NOT_SET = -1, // Not set (user or keys)
+    ALWAYS = 0, // Always happens, no modifier needed
+    SHIFT = GDK_SHIFT_MASK,
+    CTRL = GDK_CONTROL_MASK,
+    ALT = GDK_MOD1_MASK,
+    SUPER = GDK_SUPER_MASK,
+    HYPER = GDK_HYPER_MASK,
+    META = GDK_META_MASK,
+    ALL_MODS = SHIFT | CTRL | ALT | SUPER | HYPER | META,
+};
+
+// Triggers used for collision warnings, two tools are using the same trigger
+enum Triggers : Trigger {
+    NO_CATEGORY, CANVAS, SELECT, MOVE, TRANSFORM,
+    // Action taken to trigger this modifier, starts at
+    // bit 6 so categories and triggers can be combined.
+    CLICK = 32,
+    DRAG = 64,
+    SCROLL = 128,
+};
+
+/**
+ * This anonymous enum is used to provide a list of the Shifts
+ */
+enum class Type {
+    // {TOOL_NAME}_{ACTION_NAME}
+
+    // Canvas tools (applies to any tool selection)
+    CANVAS_PAN_Y,         // Pan up and down {NOTHING+SCROLL}
+    CANVAS_PAN_X,         // Pan left and right {SHIFT+SCROLL}
+    CANVAS_ZOOM,          // Zoom in and out {CTRL+SCROLL}
+    CANVAS_ROTATE,        // Rotate CW and CCW {CTRL+SHIFT+SCROLL}
+
+    // Select tool (minus transform)
+    SELECT_ADD_TO,        // Add selection {SHIFT+CLICK}
+    SELECT_IN_GROUPS,     // Select within groups {CTRL+CLICK}
+    SELECT_TOUCH_PATH,    // Draw band to select {ALT+DRAG+Nothing selected}
+    SELECT_ALWAYS_BOX,    // Draw box to select {SHIFT+DRAG}
+    SELECT_FIRST_HIT,     // Start dragging first item hit {CTRL+DRAG} (Is this an actual feature?)
+    SELECT_FORCE_DRAG,    // Drag objects even if the mouse isn't over them {ALT+DRAG+Selected}
+    SELECT_CYCLE,         // Cycle through objects under cursor {ALT+SCROLL}
+
+    // Transform handles (applies to multiple tools)
+    MOVE_CONFINE,         // Limit dragging to X OR Y only {DRAG+CTRL}
+    MOVE_INCREMENT,       // Move objects by fixed amounts {DRAG+ALT}
+    MOVE_SNAPPING,        // Disable snapping while moving {DRAG+SHIFT}
+    TRANS_CONFINE,        // Confine resize aspect ratio {HANDLE+CTRL}
+    TRANS_INCREMENT,      // Scale/Rotate/skew by fixed ratio angles {HANDLE+ALT}
+    TRANS_OFF_CENTER,     // Scale/Rotate/skew from opposite corner {HANDLE+SHIFT}
+    TRANS_SNAPPING,       // Disable snapping while transforming {HANDLE+SHIFT}
+    // TODO: Alignment omitted because it's UX is not completed
+};
+
+
+// Generate a label such as Shift+Ctrl from any KeyMask
+std::string   generate_label(KeyMask mask, std::string sep = "+");
+unsigned long calculate_weight(KeyMask mask);
+
+// Generate a responsivle tooltip set
+void responsive_tooltip(Inkscape::MessageContext *message_context, GdkEvent *event, int num_args, ...);
+
+/**
+ * A class to represent ways functionality is driven by shift modifiers
+ */
+class Modifier {
+private:
+    /** An easy to use definition of the table of modifiers by Type and ID. */
+    typedef std::map<Type, Modifier *> Container;
+    typedef std::map<std::string, Modifier *> Lookup;
+    typedef std::map<Trigger, std::string> CategoryNames;
+
+    /** A table of all the created modifiers and their ID lookups. */
+    static Container _modifiers;
+    static Lookup _modifier_lookup;
+    static CategoryNames _category_names;
+
+    char const * _id;    // A unique id used by keys.xml to identify it
+    char const * _name;  // A descriptive name used in preferences UI
+    char const * _desc;  // A more verbose description used in preferences UI
+
+    Trigger _category; // The category of tool, what it might conflict with
+    Trigger _trigger; // The type of trigger/action
+
+    // Default values if nothing is set in keys.xml
+    KeyMask _and_mask_default; // The pressed keys must have these bits set
+    unsigned long _weight_default = 0;
+
+    // User set data, set by keys.xml (or other included file)
+    KeyMask _and_mask_keys = NOT_SET;
+    KeyMask _not_mask_keys = NOT_SET;
+    unsigned long _weight_keys = 0;
+    KeyMask _and_mask_user = NOT_SET;
+    KeyMask _not_mask_user = NOT_SET;
+    unsigned long _weight_user = 0;
+
+protected:
+
+public:
+
+    char const * get_id() const { return _id; }
+    char const * get_name() const { return _name; }
+    char const * get_description() const { return _desc; }
+    Trigger get_trigger() const { return _category | _trigger; }
+
+    // Set user value
+    void set_keys(KeyMask and_mask, KeyMask not_mask) {
+        _and_mask_keys = and_mask;
+        _not_mask_keys = not_mask;
+        _weight_keys = calculate_weight(and_mask) + calculate_weight(not_mask);
+    }
+    void set_user(KeyMask and_mask, KeyMask not_mask) {
+        _and_mask_user = and_mask;
+        _not_mask_user = not_mask;
+        _weight_user = calculate_weight(and_mask) + calculate_weight(not_mask);
+    }
+    void unset_keys() { set_keys(NOT_SET, NOT_SET); }
+    void unset_user() { set_user(NOT_SET, NOT_SET); }
+    bool is_set_user() const { return _and_mask_user != NOT_SET; }
+
+    // Get value, either user defined value or default
+    KeyMask get_and_mask() {
+        if(_and_mask_user != NOT_SET) return _and_mask_user;
+        if(_and_mask_keys != NOT_SET) return _and_mask_keys;
+        return _and_mask_default;
+    }
+    KeyMask get_not_mask() {
+        // The not mask is enabled by the AND mask being set first.
+        if(_and_mask_user != NOT_SET) return _not_mask_user;
+        if(_and_mask_keys != NOT_SET) return _not_mask_keys;
+        return NOT_SET;
+    }
+    // Return number of bits set for the keys
+    unsigned long get_weight() {
+        if(_and_mask_user != NOT_SET) return _weight_user;
+        if(_and_mask_keys != NOT_SET) return _weight_keys;
+        return _weight_default;
+    }
+
+    // Generate labels such as "Shift+Ctrl" for the active modifier
+    std::string get_label() { return generate_label(get_and_mask()); }
+    std::string get_category() { return _category_names[_category]; }
+
+    // Configurations for saving the xml file
+    bool get_config_user_disabled() { return (_and_mask_user == NEVER); }
+    std::string get_config_user_and() { return generate_label(_and_mask_user, ","); }
+    std::string get_config_user_not() { return generate_label(_not_mask_keys, ","); }
+
+    /**
+     * Inititalizes the Modifier with the parameters.
+     *
+     * @param id       Goes to \c _id.
+     * @param name     Goes to \c _name.
+     * @param desc     Goes to \c _desc.
+     * @param default_ Goes to \c _default.
+     */
+    Modifier(char const * id,
+             char const * name,
+             char const * desc,
+             const KeyMask and_mask,
+             const Trigger category,
+             const Trigger trigger) :
+        _id(id),
+        _name(name),
+        _desc(desc),
+        _and_mask_default(and_mask),
+        _category(category),
+        _trigger(trigger)
+    {
+        _modifier_lookup.emplace(_id, this);
+        _weight_default = calculate_weight(and_mask);
+    }
+    // Delete the destructor, because we are eternal
+    ~Modifier() = delete;
+
+    static Type which(Trigger trigger, int button_state);
+    static std::vector<Modifier *>getList ();
+    bool active(int button_state);
+
+    /**
+     * A function to turn an enum index into a modifier object.
+     *
+     * @param  index  The enum index to be translated
+     * @return A pointer to a modifier object or a NULL if not found.
+     */
+    static Modifier * get(Type index) {
+        return _modifiers[index];
+    }
+    /**
+     * A function to turn a string id into a modifier object.
+     *
+     * @param  id  The id string to be translated
+     * @return A pointer to a modifier object or a NULL if not found.
+     */
+    static Modifier * get(char const * id) {
+        Modifier *modifier = nullptr;
+        Lookup::iterator mod_found = _modifier_lookup.find(id);
+
+        if (mod_found != _modifier_lookup.end()) {
+            modifier = mod_found->second;
+        }
+    
+        return modifier;
+    }
+
+}; // Modifier class
+
+} // namespace Modifiers
+} // namespace Inkscape
+
+
+#endif // SEEN_SP_MODIFIERS_H
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :