Finish UI for toggling "snap to canvas edge" behavior

A menu is now provided (`View > Snap to canvas edge`), and custom snap distance is changeable via `Tools > Options > Interface`.

A lot of code is required to provide a UI for this feature, since snap settings need to be persistent between sessions, but still easily toggleable in a top-level menu.

Next up: actually implementing the snap feature (sigh).

Forms/MainWindow.frm

@@ -1729,6 +1729,14 @@ Begin VB.Form FormMain
          Caption         =   "Show status bar"
          Index           =   7
       End
+      Begin VB.Menu MnuView 
+         Caption         =   "-"
+         Index           =   8
+      End
+      Begin VB.Menu MnuView 
+         Caption         =   "Snap to canvas edges"
+         Index           =   9
+      End
    End
    Begin VB.Menu MnuWindowTop 
       Caption         =   "Window"
@@ -3828,6 +3836,10 @@ Private Sub MnuView_Click(Index As Integer)
             Actions.LaunchAction_ByName "view_rulers"
         Case 7
             Actions.LaunchAction_ByName "view_statusbar"
+        Case 8
+            '(separator)
+        Case 9
+            Actions.LaunchAction_ByName "snap_canvasedge"
     End Select
 End Sub
 

Forms/Tools_Options.frm

@@ -53,10 +53,23 @@ Begin VB.Form FormOptions
       Width           =   8295
       _ExtentX        =   14631
       _ExtentY        =   11853
+      Begin PhotoDemon.pdSpinner spnSnapDistance 
+         Height          =   375
+         Left            =   120
+         TabIndex        =   44
+         Top             =   4560
+         Width           =   1935
+         _ExtentX        =   3413
+         _ExtentY        =   661
+         DefaultValue    =   8
+         Min             =   1
+         Max             =   255
+         Value           =   8
+      End
       Begin PhotoDemon.pdPictureBox picGrid 
          Height          =   735
          Left            =   150
-         Top             =   4530
+         Top             =   5610
          Width           =   735
          _ExtentX        =   1296
          _ExtentY        =   1296
@@ -133,7 +146,7 @@ Begin VB.Form FormOptions
          Height          =   810
          Left            =   1080
          TabIndex        =   2
-         Top             =   4500
+         Top             =   5580
          Width           =   3015
          _ExtentX        =   5318
          _ExtentY        =   1429
@@ -144,7 +157,7 @@ Begin VB.Form FormOptions
          Height          =   795
          Left            =   4140
          TabIndex        =   4
-         Top             =   4500
+         Top             =   5580
          Width           =   3015
          _ExtentX        =   5318
          _ExtentY        =   1402
@@ -155,7 +168,7 @@ Begin VB.Form FormOptions
          Height          =   690
          Left            =   7260
          TabIndex        =   5
-         Top             =   4560
+         Top             =   5640
          Width           =   465
          _ExtentX        =   820
          _ExtentY        =   1217
@@ -165,7 +178,7 @@ Begin VB.Form FormOptions
          Height          =   690
          Left            =   7770
          TabIndex        =   6
-         Top             =   4560
+         Top             =   5640
          Width           =   465
          _ExtentX        =   820
          _ExtentY        =   1217
@@ -175,7 +188,7 @@ Begin VB.Form FormOptions
          Height          =   285
          Index           =   2
          Left            =   0
-         Top             =   4080
+         Top             =   5160
          Width           =   8205
          _ExtentX        =   14473
          _ExtentY        =   503
@@ -205,6 +218,18 @@ Begin VB.Form FormOptions
          ForeColor       =   4210752
          Layout          =   2
       End
+      Begin PhotoDemon.pdLabel lblTitle 
+         Height          =   285
+         Index           =   23
+         Left            =   0
+         Top             =   4080
+         Width           =   8100
+         _ExtentX        =   14288
+         _ExtentY        =   503
+         Caption         =   "snap distance (in pixels)"
+         FontSize        =   12
+         ForeColor       =   4210752
+      End
    End
    Begin PhotoDemon.pdContainer picContainer 
       Height          =   6720
@@ -1180,10 +1205,12 @@ Private Sub cmdBarMini_OKClick()
         g_RecentMacros.MRU_NotifyNewMaxLimit
     End If
 
+    UserPrefs.SetPref_Long "Interface", "snap-distance", spnSnapDistance.Value
+    Tools_Move.SetSnapDistance spnSnapDistance.Value
+
     UserPrefs.SetPref_Long "Transparency", "Alpha Check Mode", CLng(cboAlphaCheck.ListIndex)
     UserPrefs.SetPref_Long "Transparency", "Alpha Check One", CLng(csAlphaOne.Color)
     UserPrefs.SetPref_Long "Transparency", "Alpha Check Two", CLng(csAlphaTwo.Color)
-
     UserPrefs.SetPref_Long "Transparency", "Alpha Check Size", cboAlphaCheckSize.ListIndex
     Drawing.CreateAlphaCheckerboardDIB g_CheckerboardPattern
 
@@ -1408,6 +1435,7 @@ Private Sub LoadAllPreferences()
     csCanvasColor.Color = UserPrefs.GetCanvasColor()
     tudRecentFiles.Value = UserPrefs.GetPref_Long("Interface", "Recent Files Limit", 10)
     btsMRUStyle.ListIndex = UserPrefs.GetPref_Long("Interface", "MRU Caption Length", 0)
+    spnSnapDistance.Value = UserPrefs.GetPref_Long("Interface", "snap-distance", 8&)
     m_userInitiatedAlphaSelection = False
     cboAlphaCheck.ListIndex = UserPrefs.GetPref_Long("Transparency", "Alpha Check Mode", 0)
     csAlphaOne.Color = UserPrefs.GetPref_Long("Transparency", "Alpha Check One", RGB(255, 255, 255))

Modules/Actions.bas

@@ -1299,6 +1299,7 @@ Private Function Launch_ByName_MenuView(ByRef srcMenuName As String, Optional By
     If (Not PDImages.IsImageActive()) Then Exit Function
 
     Dim cmdFound As Boolean: cmdFound = True
+    Dim newState As Boolean
 
     Select Case srcMenuName
 
@@ -1344,16 +1345,17 @@ Private Function Launch_ByName_MenuView(ByRef srcMenuName As String, Optional By
                 If FormMain.MainCanvas(0).IsZoomEnabled Then FormMain.MainCanvas(0).SetZoomDropDownIndex 21
 
         Case "view_rulers"
-            Dim newRulerState As Boolean
-            newRulerState = Not FormMain.MainCanvas(0).GetRulerVisibility()
-            FormMain.MnuView(6).Checked = newRulerState
-            FormMain.MainCanvas(0).SetRulerVisibility newRulerState
+            newState = Not FormMain.MainCanvas(0).GetRulerVisibility()
+            FormMain.MnuView(6).Checked = newState
+            FormMain.MainCanvas(0).SetRulerVisibility newState
 
         Case "view_statusbar"
-            Dim newStatusBarState As Boolean
-            newStatusBarState = Not FormMain.MainCanvas(0).GetStatusBarVisibility()
-            FormMain.MnuView(7).Checked = newStatusBarState
-            FormMain.MainCanvas(0).SetStatusBarVisibility newStatusBarState
+            newState = Not FormMain.MainCanvas(0).GetStatusBarVisibility()
+            FormMain.MnuView(7).Checked = newState
+            FormMain.MainCanvas(0).SetStatusBarVisibility newState
+
+        Case "snap_canvasedge"
+            Interface.ToggleSnapOptions pdst_CanvasEdge
 
         Case Else
             cmdFound = False
@@ -2000,6 +2002,7 @@ Public Sub BuildActionDatabase()
     AddAction "zoom_1_16", vbNullString
     AddAction "view_rulers", vbNullString
     AddAction "view_statusbar", vbNullString
+    AddAction "snap_canvasedge", vbNullString
     'AddAction "window_toolbox"
     AddAction "window_displaytoolbox", vbNullString
     AddAction "window_displaytoolcategories", vbNullString

Modules/Interface.bas

@@ -1210,6 +1210,30 @@ Public Sub ToggleImageTabstripVisibility(ByVal newSetting As Long, Optional ByVa
 
 End Sub
 
+'Toggle one of the "snap to..." settings in the View menu.
+' To forcibly set to a specific state (instead of toggling), set the forceInsteadOfToggle param to TRUE.
+Public Sub ToggleSnapOptions(ByVal snapTarget As PD_SnapTargets, Optional ByVal forceInsteadOfToggle As Boolean = False, Optional ByVal newState As Boolean = True)
+
+    'Convert the snap target into a menu index
+    Const IDX_BASE As Long = 9
+    Dim idxTarget As Long
+
+    'While calculating which on-screen menu to update, we also need to relay changes to two places:
+    ' 1) the tools_move module (which handles actual snap calculations)
+    ' 2) the user preferences file (to ensure everything is synchronized between sessions)
+    Select Case snapTarget
+        Case pdst_CanvasEdge
+            idxTarget = IDX_BASE + 0
+            If (Not forceInsteadOfToggle) Then newState = Not Tools_Move.GetSnapCanvasEdge()
+            Tools_Move.SetSnapCanvasEdge newState
+            UserPrefs.SetPref_Boolean "Interface", "snap-canvas-edge", newState
+    End Select
+
+    'Update the target menu state
+    FormMain.MnuView(idxTarget).Checked = newState
+
+End Sub
+
 Public Function FixDPI(ByVal pxMeasurement As Long) As Long
 
     'The first time this function is called, m_DPIRatio will be 0.  Calculate it.

Modules/Menus.bas

@@ -590,6 +590,8 @@ Public Sub InitializeMenus()
     AddMenuItem "-", "-", 8, 5
     AddMenuItem "Show rulers", "view_rulers", 8, 6
     AddMenuItem "Show status bar", "view_statusbar", 8, 7
+    AddMenuItem "-", "-", 8, 8
+    AddMenuItem "Snap to canvas edge", "snap_canvasedge", 8, 9
 
     'Window Menu
     AddMenuItem "Window", "window_top", 9

Modules/MoveTool.bas

@@ -3,24 +3,34 @@ Attribute VB_Name = "Tools_Move"
 'PhotoDemon Move/Size Tool Manager
 'Copyright 2014-2024 by Tanner Helland
 'Created: 24/May/14
-'Last updated: 22/December/22
-'Last update: add some trivial key-handling bits for the Hand tool (which is a different tool, but it has
-'             so few features that it's easier to just condense things here)
+'Last updated: 05/April/24
+'Last update: start wiring up Snap capabilities
 '
 'This module interfaces between the layer move/size UI and actual layer backend.  Look in the relevant
 ' tool panel form for more details on how the UI relays relevant tool data here.
 '
+'As of 2024, This module also handles move-related duties like snapping to various features.
+'
 'Unless otherwise noted, all source code in this file is shared under a simplified BSD license.
 ' Full license details are available in the LICENSE.md file, or at https://photodemon.org/license/
 '
 '***************************************************************************
 
 Option Explicit
 
+Public Enum PD_SnapTargets
+    pdst_CanvasEdge
+End Enum
+
+#If False Then
+    Private Const pdst_CanvasEdge = 0
+#End If
+
 'The move/size tool exposes a number of UI-only options (like drawing borders around active layers).
 ' To improve viewport performance, we cache those settings locally, and the viewport queries us instead
 ' of directly querying the associated UI elements.
 Private m_DrawLayerBorders As Boolean, m_DrawCornerNodes As Boolean, m_DrawRotateNodes As Boolean
+Private m_SnapToCanvasEdge As Boolean, m_SnapDistance As Long
 
 'Same goes for various selection-related move settings (for moving selected pixels).  These are simple
 ' flags whose value is relayed from the Move/Size options panel.
@@ -315,6 +325,19 @@ Public Function GetDrawLayerRotateNodes() As Boolean
     GetDrawLayerRotateNodes = m_DrawRotateNodes
 End Function
 
+Public Function GetSnapCanvasEdge() As Boolean
+    GetSnapCanvasEdge = m_SnapToCanvasEdge
+End Function
+
+Public Function GetSnapDistance() As Long
+
+    GetSnapDistance = m_SnapDistance
+
+    'Failsafe only; should never trigger
+    If (GetSnapDistance < 1) Then GetSnapDistance = 8
+
+End Function
+
 Public Sub SetDrawLayerBorders(ByVal newState As Boolean)
     m_DrawLayerBorders = newState
 End Sub
@@ -327,6 +350,16 @@ Public Sub SetDrawLayerRotateNodes(ByVal newState As Boolean)
     m_DrawRotateNodes = newState
 End Sub
 
+Public Sub SetSnapCanvasEdge(ByVal newState As Boolean)
+    m_SnapToCanvasEdge = newState
+End Sub
+
+Public Sub SetSnapDistance(ByVal newDistance As Long)
+    m_SnapDistance = newDistance
+    If (m_SnapDistance < 1) Then m_SnapDistance = 1
+    If (m_SnapDistance > 255) Then m_SnapDistance = 255     'GIMP uses a 255 max value; that seems reasonable
+End Sub
+
 'Relay functions for move selected pixels behavior
 Public Function GetMoveSelectedPixels_DefaultCut() As Boolean
     GetMoveSelectedPixels_DefaultCut = m_SelectionDefaultCut

Modules/UserPrefs.bas

@@ -5,7 +5,7 @@ Attribute VB_Name = "UserPrefs"
 'Created: 03/November/12
 'Last updated: 21/February/22
 'Last update: revert nightly builds to default to "nightly build" update track (I've gotten much better
-'             at disciplined nightly build development, and they are far more stable than the used to be).
+'             at disciplined nightly build development, and they are far more stable than they used to be).
 '
 'This is the modern incarnation of PD's old "INI file" module.  It is responsible for managing all
 ' persistent user settings.
@@ -609,6 +609,9 @@ Public Sub LoadUserSettings()
         Tools.SetToolSetting_HighResMouse UserPrefs.GetPref_Boolean("Tools", "HighResMouseInput", True)
         m_CanvasColor = Colors.GetRGBLongFromHex(UserPrefs.GetPref_String("Interface", "CanvasColor", "#a0a0a0"))
 
+        Interface.ToggleSnapOptions pdst_CanvasEdge, True, UserPrefs.GetPref_Boolean("Interface", "snap-canvas-edge", True)
+        Tools_Move.SetSnapDistance UserPrefs.GetPref_Long("Interface", "snap-distance", 8&)
+
         'Users can supply a (secret!) "UIFont" setting in the "Interface" segment if they
         ' want to override PD's default font object.
         m_UIFontName = UserPrefs.GetPref_String("Interface", "UIFont", vbNullString, False)

PhotoDemon.vbp

@@ -526,7 +526,7 @@ Description="PhotoDemon Photo Editor"
 CompatibleMode="0"
 MajorVer=9
 MinorVer=1
-RevisionVer=347
+RevisionVer=348
 AutoIncrementVer=1
 ServerSupportFiles=0
 VersionComments="Copyright 2000-2024 Tanner Helland - photodemon.org"