Fix #404, percent layout values implemented in V/H layout.

Only one widget with percent value allowed per layout.

src/dlangui/widgets/layouts.d

@@ -26,6 +26,7 @@ Authors:   Vadim Lopatin, coolreader.org@gmail.com
 module dlangui.widgets.layouts;
 
 public import dlangui.widgets.widget;
+import std.conv;
 
 /// helper for layouts
 struct LayoutItem {
@@ -109,12 +110,31 @@ class LayoutItems {
         _maxSecondarySize = 0;
         _measureParentSize.x = parentWidth;
         _measureParentSize.y = parentHeight;
+        // bool
+        bool hasPercentSizeWidget = false;
+        size_t percenSizeWidgetIndex;
         // measure
         for (int i = 0; i < _count; i++) {
             LayoutItem * item = &_list[i];
+            
             item.measure(parentWidth, parentHeight);
+            
+            if (isPercentSize(item._layoutSize)) {
+                if (!hasPercentSizeWidget) {
+                    percenSizeWidgetIndex = i;
+                    hasPercentSizeWidget = true;
+                }
+            } 
+            else
+                _totalSize += item._measuredSize;
+            
             if (_maxSecondarySize < item._secondarySize)
                 _maxSecondarySize = item._secondarySize;
+        }
+        if (hasPercentSizeWidget) {
+            LayoutItem * item = &_list[percenSizeWidgetIndex];
+            
+            item._measuredSize = to!int(_totalSize * ((1 / (1 - cast (double) (fromPercentSize(item._layoutSize, 100))/100)) - 1));
             _totalSize += item._measuredSize;
         }
         return _orientation == Orientation.Horizontal ? Point(_totalSize, _maxSecondarySize) : Point(_maxSecondarySize, _totalSize);
@@ -161,7 +181,7 @@ class LayoutItems {
                 maxItem = item.secondarySize;
             if (item._isResizer) {
                 resizersSize += size;
-            } else if (item.fillParent) {
+            } else if (item.fillParent || isPercentSize(item.layoutSize)) {
                 resizableWeight += weight;
                 resizableSize += size * weight;
             } else {
@@ -174,7 +194,7 @@ class LayoutItems {
                 contentSecondarySize = maxItem;
             else
                 contentSecondarySize = rc.width;
-            if (_layoutHeight == FILL_PARENT && totalSize < rc.height && resizableSize > 0) {
+            if ((_layoutHeight == FILL_PARENT || isPercentSize(_layoutHeight)) && totalSize < rc.height && resizableSize > 0) {
                 delta = rc.height - totalSize; // total space to add to fit
             } else if (totalSize > rc.height) {
                 delta = rc.height - totalSize; // total space to reduce to fit
@@ -184,7 +204,7 @@ class LayoutItems {
                 contentSecondarySize = maxItem;
             else
                 contentSecondarySize = rc.height;
-            if (_layoutWidth == FILL_PARENT && totalSize < rc.width && resizableSize > 0)
+            if ((_layoutWidth == FILL_PARENT || isPercentSize(_layoutHeight)) && totalSize < rc.width && resizableSize > 0)
                 delta = rc.width - totalSize; // total space to add to fit
             else if (totalSize > rc.width)
                 delta = rc.width - totalSize; // total space to reduce to fit
@@ -216,7 +236,7 @@ class LayoutItems {
         int resizerDelta = 0;
         for (int i = 0; i < _count; i++) {
             LayoutItem * item = &_list[i];
-            if ((item.fillParent || needForceResize) && (delta < 0 || item.canExtend)) {
+            if ((item.fillParent || isPercentSize(item.layoutSize) || needForceResize) && (delta < 0 || item.canExtend)) {
                 lastResized = i;
             }
             if (item._isResizer) {
@@ -232,7 +252,7 @@ class LayoutItems {
             int layoutSize = item.layoutSize;
             int weight = item.weight;
             int size = item.measuredSize;
-            if (needResize && (layoutSize == FILL_PARENT || needForceResize)) {
+            if (needResize && (layoutSize == FILL_PARENT || isPercentSize(layoutSize) || needForceResize)) {
                 // do resize
                 int correction = (delta < 0 || item.canExtend) ? scaleFactor * weight * size / 10000 : 0;
                 deltaTotal += correction;

src/dlangui/widgets/widget.d

@@ -623,9 +623,9 @@ public:
     /// set max height constraint (0 for no constraint)
     @property Widget minHeight(int value) { ownStyle.minHeight = value; return this; }
 
-    /// returns layout width options (WRAP_CONTENT, FILL_PARENT, or some constant value)
+    /// returns layout width options (WRAP_CONTENT, FILL_PARENT, some constant value or percent but only for one widget in layout)
     @property int layoutWidth() { return style.layoutWidth; }
-    /// returns layout height options (WRAP_CONTENT, FILL_PARENT, or some constant value)
+    /// returns layout height options (WRAP_CONTENT, FILL_PARENT, some constant value or percent but only for one widget in layout)
     @property int layoutHeight() { return style.layoutHeight; }
     /// returns layout weight (while resizing to fill parent, widget will be resized proportionally to this value)
     @property int layoutWeight() { return style.layoutWeight; }
@@ -1371,13 +1371,10 @@ public:
         // check for fixed size set in layoutWidth, layoutHeight
         int lh = layoutHeight;
         int lw = layoutWidth;
-        if (isPercentSize(lh) && parentHeight != SIZE_UNSPECIFIED)
+        // constant value support
-            dy = fromPercentSize(lh, parentHeight);
+        if (!(isPercentSize(lh) || isSpecialSize(lh)))
-        else if (!isSpecialSize(lh))
             dy = lh;
-        if (isPercentSize(lw) && parentWidth != SIZE_UNSPECIFIED)
+        if (!(isPercentSize(lw) || isSpecialSize(lw)))
-            dx = fromPercentSize(lw, parentWidth);
-        else if (!isSpecialSize(lw))
             dx = lw;
         // apply min/max width and height constraints
         int minw = minWidth;