feat(ios): allow inline calendar to fill available width

ios/RNDateTimePicker.m

@@ -72,4 +72,21 @@ - (void)setDate:(NSDate *)date {
     }
 }
 
+- (CGSize)intrinsicContentSize {
+    CGSize size = [super intrinsicContentSize];
+    // iOS DatePicker requires a minimum width of 280 points for proper display
+    // See: https://github.com/react-native-datetimepicker/datetimepicker/issues/1014
+    size.width = MAX(size.width, 280);
+
+    // For inline (calendar) display style, suggest a larger width
+    // This helps the calendar expand to fill available width
+    if (@available(iOS 14.0, *)) {
+        if (self.preferredDatePickerStyle == UIDatePickerStyleInline) {
+            size.width = MAX(size.width, 375); // Standard iPhone width
+        }
+    }
+
+    return size;
+}
+
 @end

ios/RNDateTimePickerShadowView.m

@@ -69,7 +69,30 @@ static YGSize RNDateTimePickerShadowViewMeasure(YGNodeConstRef node, float width
     }
 
     size = [shadowPickerView.picker sizeThatFits:UILayoutFittingCompressedSize];
-    size.width += 10;
+    // iOS DatePicker requires a minimum width of 280 points for proper display
+    // See: https://github.com/react-native-datetimepicker/datetimepicker/issues/1014
+    size.width = MAX(size.width, 280);
+
+    // Respect the provided width constraint to allow the picker to expand to full width
+    // when a specific width is provided or when measuring at-most mode
+    if (widthMode == YGMeasureModeExactly) {
+      size.width = width;
+    } else if (widthMode == YGMeasureModeAtMost) {
+      // For inline/calendar style, try to use the full available width
+      // For other styles, use the minimum width needed
+      if (@available(iOS 14.0, *)) {
+        if (shadowPickerView.picker.preferredDatePickerStyle == UIDatePickerStyleInline) {
+          size.width = width; // Use full available width for calendar
+        } else {
+          size.width = MIN(size.width + 10, width);
+        }
+      } else {
+        size.width = MIN(size.width + 10, width);
+      }
+    } else {
+      // For undefined mode, add small padding
+      size.width += 10;
+    }
   });
 
   return (YGSize){

ios/fabric/RNDateTimePickerComponentView.mm

@@ -103,7 +103,24 @@ - (void) updateMeasurements {
         return;
     }
     CGSize size = [_dummyPicker sizeThatFits:UILayoutFittingCompressedSize];
-    size.width += 10;
+    // iOS DatePicker requires a minimum width of 280 points for proper display
+    // See: https://github.com/react-native-datetimepicker/datetimepicker/issues/1014
+    size.width = MAX(size.width, 280);
+
+    // For inline (calendar) display style, use a larger default width to fill the container
+    // The actual width will be constrained by the parent container's layout
+    if (@available(iOS 14.0, *)) {
+        if (_dummyPicker.preferredDatePickerStyle == UIDatePickerStyleInline) {
+            // Use a large width that will be constrained by the parent
+            // This allows the calendar to expand to full width of its container
+            size.width = 375; // Standard iPhone width, will be constrained by parent if smaller
+        } else {
+            size.width += 10;
+        }
+    } else {
+        size.width += 10;
+    }
+
     auto newState = RNDateTimePickerState{RCTSizeFromCGSize(size)};
     _state->updateState(std::move(newState));
 }