Ticket #5203: deskcalc-wim.diff

deskcalc/ExpressionTextView.cpp

@@ -30 +30 @@
     fKeypadLabels(""),
     fPreviousExpressions(20),
     fHistoryPos(0),
-    fCurrentExpression("")
+    fCurrentExpression(""),
+    fCurrentValue(""),
+    fChangesApplied(false)
 {
     SetStylable(false);
     SetDoesUndo(true);
@@ -91 +93 @@
     // end of the expression history
     if (current != Text())
         fHistoryPos = fPreviousExpressions.CountItems();
+        
+    // if changes where not applied the value has become a new expression
+    // note that even if only the left or right arrow keys are pressed the
+    // fCurrentValue string will be cleared
+    if (!fChangesApplied)
+        fCurrentValue.SetTo("");
+    else
+        fChangesApplied = false;
 }
 
 
@@ -117 +127 @@
 }
 
 
+void
+ExpressionTextView::SetTextRect(BRect rect)
+{
+    InputTextView::SetTextRect(rect);
+    
+    int32 count = fPreviousExpressions.CountItems();
+    if (fHistoryPos == count && fCurrentValue.CountChars() > 0) {
+        SetValue(fCurrentValue.String());
+    }
+}
+
+
 // #pragma mark -
 
 
@@ -133 +155 @@
     AddExpressionToHistory(Text());
     fCalcView->FlashKey("=", 1);
     fCalcView->Evaluate();
+    fChangesApplied = true;
 }
 
 
@@ -156 +179 @@
 
 
 void
+ExpressionTextView::SetValue(const char* value)
+{
+    // copy the value string so we can modify it
+    BString val(value);
+    
+    // save the value
+    fCurrentValue = val;
+
+    // calculate the width of the string
+    BFont font;
+    uint32 mode = B_FONT_ALL;
+    GetFontAndColor(&font, &mode);
+    float stringWidth = font.StringWidth(val);
+    
+    // make the string shorter if it does not fit in the view
+    float viewWidth = Frame().Width();
+    if (val.CountChars() > 3 && stringWidth > viewWidth) {
+        
+        // get the position of the first digit
+        int32 firstDigit = 0;
+        if (val[0] == '-')
+            firstDigit++;
+
+        // calculate the value of the exponent
+        int32 exponent = 0;
+        int32 offset = val.FindFirst('.');
+        if (offset == B_ERROR) {
+            exponent = val.CountChars() - 1 - firstDigit;
+            val.Insert('.', 1, firstDigit + 1);
+        } else {
+            if (offset == firstDigit + 1) {
+                // if the value is 0.01 or larger then scientific notation
+                // won't shorten the string
+                if (val[firstDigit] != '0' || val[firstDigit+2] != '0' 
+                    || val[firstDigit+3] != '0') {
+                        exponent = 0;
+                } else {
+                    // remove the period
+                    val.Remove(offset, 1);
+                    
+                    // check for negative exponent value
+                    exponent = 0;
+                    while (val[firstDigit] == '0') {
+                        val.Remove(firstDigit, 1);
+                        exponent--;
+                    }
+                    
+                    //add the period
+                    val.Insert('.', 1, firstDigit + 1);
+                }
+            } else {
+                // if the period + 1 digit fits in the view scientific notation
+                // won't shorten the string
+                BString temp = val;
+                temp.Truncate(offset + 2);
+                stringWidth = font.StringWidth(temp);
+                if (stringWidth < viewWidth) {
+                    exponent = 0;
+                } else {
+                    // move the period
+                    val.Remove(offset, 1);
+                    val.Insert('.', 1, firstDigit + 1);
+                    
+                    exponent = offset - (firstDigit + 1);
+                }
+            }
+        }
+        
+        // add the exponent
+        offset = val.CountChars() - 1;
+        if (exponent != 0)
+            val << "E" << exponent;
+        
+        // reduce the number of digits until the string fits or can not be
+        // made any shorter
+        stringWidth = font.StringWidth(val);
+        char lastRemovedDigit = '0';
+        while (offset > firstDigit && stringWidth > viewWidth) {
+            if (val[offset] != '.') 
+                lastRemovedDigit = val[offset];
+            val.Remove(offset--, 1);
+            stringWidth = font.StringWidth(val);
+        }
+        
+        // there is no need to keep the period if no digits follow
+        if (val[offset] == '.') {
+            val.Remove(offset, 1);
+            offset--;
+        }
+        
+        // take care of proper rounding of the result
+        int digit = (int)lastRemovedDigit - 48; // ascii to int
+        if (digit >= 5) {
+            for (; offset >= firstDigit; offset--) {
+                if (val[offset] == '.')
+                    continue;
+                digit = (int)(val[offset]) - 47; // ascii to int + 1
+                if (digit != 10) break;
+                val.Remove(offset, 1);
+            }
+            if (digit == 10) {
+                // carry over, shift the result
+                if (val[firstDigit+1] == '.') {
+                    val[firstDigit+1] = '0';
+                    val[firstDigit] = '.';
+                }
+                val.Insert('1', 1, firstDigit);
+                
+                //remove the exponent value and the last digit
+                offset = val.FindFirst('E');
+                if (offset == B_ERROR) 
+                    offset = val.CountChars();
+                val.Truncate(--offset);
+                offset--; //offset now points to the last digit
+                
+                // increase the exponent and add it back to the string
+                exponent++;
+                val << 'E' << exponent;
+            } else {
+                // increase the current digit value with one
+                val[offset] = char(digit + 48);
+            }
+        }
+        
+        // remove trailing zeros
+        while (val[offset] == '0')
+            val.Remove(offset--, 1);
+        
+        // there is no need to keep the period if no digits follow
+        if (val[offset] == '.')
+            val.Remove(offset, 1);
+    }
+
+    // set the new value    
+    SetExpression(val);
+}
+
+
+void
 ExpressionTextView::BackSpace()
 {
     const char bytes[1] = { B_BACKSPACE };

deskcalc/ExpressionTextView.h

@@ -32 +32 @@
     virtual void                GetDragParameters(BMessage* dragMessage,
                                     BBitmap** bitmap, BPoint* point,
                                     BHandler** handler);
+            void                SetTextRect(BRect rect);
 
     // InputTextView
     virtual void                RevertChanges();
@@ -41 +42 @@
             void                AddKeypadLabel(const char* label);
 
             void                SetExpression(const char* expression);
+            void                SetValue(const char* value);
 
             void                BackSpace();
             void                Clear();
@@ -59 +61 @@
             BList               fPreviousExpressions;
             int32               fHistoryPos;
             BString             fCurrentExpression;
+            BString             fCurrentValue;
+            
+            bool                fChangesApplied;
 };
 
 #endif // EXPRESSION_TEXT_VIEW_H

deskcalc/CalcView.cpp

@@ -917 +917 @@
     }
 
     // render new result to display
-    fExpressionTextView->SetExpression(value.String());
+    fExpressionTextView->SetValue(value.String());
 }