[ui] expressionTextField : move evaluation to python

Author: Alxiice

meshroom/core/evaluation.py

@@ -0,0 +1,48 @@
+#!/usr/bin/env python
+
+import ast, math
+
+
+class MathEvaluator:
+    """ Evaluate math expressions
+    
+    ..code::py
+        # Example usage
+        mev = MathEvaluator()
+        print(mev.evaluate("e-1+cos(2*pi)"))
+        print(mev.evaluate("pow(2, 8)"))
+        print(mev.evaluate("round(sin(pi), 3)"))
+    """
+    
+    # Allowed math symbols
+    allowed_symbols = {
+        "e": math.e, "pi": math.pi,
+        "cos": math.cos, "sin": math.sin, "tan": math.tan, "exp": math.exp,
+        "pow": pow, "round": round, "abs": abs, "min": min, "max": max,
+        "sqrt": math.sqrt, "log": math.log
+    }
+    # Allowed AST node types
+    allowed_nodes = (
+        ast.Expression, ast.BinOp, ast.UnaryOp, ast.Call, ast.Name, ast.Load,
+        ast.Add, ast.Sub, ast.Mult, ast.Div, ast.Pow, ast.Mod, ast.FloorDiv,
+        ast.USub, ast.UAdd, ast.BitXor, ast.BitOr, ast.BitAnd,
+        ast.LShift, ast.RShift, ast.Invert,
+        ast.Constant
+    )
+    def _validate_ast(self, node):
+        for child in ast.walk(node):
+            if not isinstance(child, self.allowed_nodes):
+                raise ValueError(f"Bad expression: {ast.dump(child)}")
+            # Check that all variable/function names are whitelisted
+            if isinstance(child, ast.Name):
+                if child.id not in self.allowed_symbols:
+                    raise ValueError(f"Unknown symbol: {child.id}")
+    def evaluate(self, expr: str):
+        if any(bad in expr for bad in ('\n', '#')):
+            raise ValueError(f"Invalid expression: {expr}")
+        try:
+            node = ast.parse(expr.strip(), mode="eval")
+            self._validate_ast(node)
+            return eval(compile(node, "<expr>", "eval"), {"__builtins__": {}}, self.allowed_symbols)
+        except Exception:
+            raise ValueError(f"Invalid expression: {expr}")

meshroom/ui/qml/Utils/ExpressionTextField.qml

@@ -41,15 +41,15 @@ TextField {
     }
 
     function getEvalExpression(_text) {
-        try {
-            var result = MathEvaluator.eval(_text)
+        var [_res, _err] = _reconstruction.evaluateMathExpression(_text)
+        if (_err == false) {
             if (isInt)
-                result = Math.round(result)
+                _res = Math.round(_res)
             else
-                result = result.toFixed(decimals)
-            return result
-        } catch (err) {
-            console.error("Error evaluating expression (", _text, "):", err)
+                _res = _res.toFixed(decimals)
+            return _res
+        } else {
+            console.error("Error evaluating expression (", _text, "):", _err)
             return NaN
         }
     }
@@ -63,24 +63,28 @@ TextField {
     }
 
     function updateExpression() {
+        var previousEvaluatedValue = evaluatedValue
         var result = getEvalExpression(root.text)
+        console.log("[ExpressionTextField] updateExpression", root.text, "->", result)
         if (!isNaN(result)) {
             evaluatedValue = result
             clearError()
-            return result
+            // return result
         } else {
-            evaluatedValue = NaN
+            evaluatedValue = previousEvaluatedValue
             raiseError()
-            return NaN
+            // return NaN
         }
     }
 
     // When user commits input, evaluate but do NOT overwrite text
     onAccepted: {
+        console.log("[ExpressionTextField] onAccepted", root.text)
         updateExpression()
     }
 
     onEditingFinished: {
+        console.log("[ExpressionTextField] onEditingFinished", root.text)
         updateExpression()
     }
 
@@ -91,6 +95,7 @@ TextField {
     }
 
     Component.onCompleted: {
+        console.log("[ExpressionTextField] onCompleted", root.text)
         refreshStatus()
     }
 }

meshroom/ui/qml/Viewer/HdrImageToolbar.qml

@@ -129,15 +129,15 @@ FloatingPane {
                 selectByMouse: true
                 onAccepted: {
                     if (!gainLabel.hasExprError) {
-                        if (gainLabel.evaluatedValue <= 0) {
-                            gainLabel.evaluatedValue = 0
-                            gainCtrl.value = gainLabel.evaluatedValue
+                        if (gainLabel.text <= 0) {
+                            gainLabel.text = 0
+                            gainCtrl.value = gainLabel.text
                         } else {
-                            gainCtrl.value = Math.pow(Number(gainLabel.evaluatedValue), 1.0 / slidersPowerValue)
+                            gainCtrl.value = Math.pow(Number(gainLabel.text), 1.0 / slidersPowerValue)
                         }
                     } else {
-                        gainLabel.evaluatedValue = 0
-                        gainCtrl.value = gainLabel.evaluatedValue
+                        // gainLabel.text = 0
+                        // gainCtrl.value = gainLabel.text
                     }
                 }
             }
@@ -180,6 +180,7 @@ FloatingPane {
                 Layout.preferredWidth: textMetrics_gainValue.width
                 selectByMouse: true
                 onAccepted: {
+                    console.log("[GammaTextField] onAccepted")
                     if (!gammaLabel.hasExprError) {
                         if (gammaLabel.evaluatedValue <= 0) {
                             gammaLabel.evaluatedValue = 0
@@ -188,8 +189,8 @@ FloatingPane {
                             gammaCtrl.value = Math.pow(Number(gammaLabel.evaluatedValue), 1.0 / slidersPowerValue)
                         }
                     } else {
-                        gainLabel.evaluatedValue = 0
-                        gainCtrl.value = gainLabel.evaluatedValue
+                        // gammaLabel.evaluatedValue = 0
+                        // gammaCtrl.value = gainLabel.evaluatedValue
                     }
                 }
             }

meshroom/ui/reconstruction.py

@@ -18,6 +18,7 @@
 from meshroom.core import Version
 from meshroom.core.node import Node, CompatibilityNode, Status, Position, CompatibilityIssue
 from meshroom.core.taskManager import TaskManager
+from meshroom.core.evaluation import MathEvaluator
 
 from meshroom.ui import commands
 from meshroom.ui.graph import UIGraph
@@ -1166,6 +1167,20 @@ def setCurrentViewPath(self, path):
         self._currentViewPath = path
         self.currentViewPathChanged.emit()
 
+    @Slot(str, result="QVariantList")
+    def evaluateMathExpression(self, expr):
+        """ Evaluate a mathematical expression and return the result as a string 
+        Returns a list of 2 values :
+        - the result value
+        - a boolean that indicate if an error occured
+        """
+        mev = MathEvaluator()
+        try:
+            res = mev.evaluate(expr)
+            return [res, False]
+        except Exception as err:
+            return [None, err]
+
     selectedViewIdChanged = Signal()
     selectedViewId = Property(str, lambda self: self._selectedViewId, setSelectedViewId, notify=selectedViewIdChanged)
     selectedViewpointChanged = Signal()