do not allow selection of invalid metatiles

- also display invalid metatiles as magenta to stand out more

include/core/tileset.h

@@ -35,6 +35,7 @@ public:
     static Metatile* getMetatile(int, Tileset*, Tileset*);
     static QList<QList<QRgb>> getBlockPalettes(Tileset*, Tileset*);
     static QList<QRgb> getPalette(int, Tileset*, Tileset*);
+    static bool metatileIsValid(uint16_t metatileId, Tileset *, Tileset *);
 
     bool appendToHeaders(QString headerFile, QString friendlyName);
     bool appendToGraphics(QString graphicsFile, QString friendlyName, bool primary);

include/ui/metatileselector.h

@@ -48,6 +48,7 @@ private:
     void updateSelectedMetatiles();
     uint16_t getMetatileId(int x, int y);
     QPoint getMetatileIdCoords(uint16_t);
+    bool shouldAcceptEvent(QGraphicsSceneMouseEvent*);
 
 signals:
     void hoveredMetatileSelectionChanged(uint16_t);

src/core/tileset.cpp

@@ -66,6 +66,19 @@ Metatile* Tileset::getMetatile(int index, Tileset *primaryTileset, Tileset *seco
     return metatile;
 }
 
+bool Tileset::metatileIsValid(uint16_t metatileId, Tileset *primaryTileset, Tileset *secondaryTileset) {
+    if (metatileId >= Project::getNumMetatilesTotal())
+        return false;
+
+    if (metatileId < Project::getNumMetatilesPrimary() && metatileId >= primaryTileset->metatiles->length())
+        return false;
+
+    if (metatileId < Project::getNumMetatilesTotal() && metatileId >= Project::getNumMetatilesPrimary() + secondaryTileset->metatiles->length())
+        return false;
+
+    return true;
+}
+
 QList<QList<QRgb>> Tileset::getBlockPalettes(Tileset *primaryTileset, Tileset *secondaryTileset) {
     QList<QList<QRgb>> palettes;
     for (int i = 0; i < Project::getNumPalettesPrimary(); i++) {

src/ui/imageproviders.cpp

@@ -18,13 +18,13 @@ QImage getMetatileImage(uint16_t tile, Tileset *primaryTileset, Tileset *seconda
 
     Metatile* metatile = Tileset::getMetatile(tile, primaryTileset, secondaryTileset);
     if (!metatile || !metatile->tiles) {
-        metatile_image.fill(0xffffffff);
+        metatile_image.fill(Qt::magenta);
         return metatile_image;
     }
 
     Tileset* blockTileset = Tileset::getBlockTileset(tile, primaryTileset, secondaryTileset);
     if (!blockTileset) {
-        metatile_image.fill(0xffffffff);
+        metatile_image.fill(Qt::magenta);
         return metatile_image;
     }
     QList<QList<QRgb>> palettes = Tileset::getBlockPalettes(primaryTileset, secondaryTileset);

src/ui/metatileselector.cpp

@@ -24,6 +24,7 @@ void MetatileSelector::draw() {
         height_++;
     }
     QImage image(this->numMetatilesWide * 16, height_ * 16, QImage::Format_RGBA8888);
+    image.fill(Qt::magenta);
     QPainter painter(&image);
     for (int i = 0; i < length_; i++) {
         int tile = i;
@@ -91,13 +92,20 @@ void MetatileSelector::setExternalSelection(int width, int height, QList<uint16_
     emit selectedMetatilesChanged();
 }
 
+bool MetatileSelector::shouldAcceptEvent(QGraphicsSceneMouseEvent *event) {
+    QPoint pos = this->getCellPos(event->pos());
+    return Tileset::metatileIsValid(getMetatileId(pos.x(), pos.y()), this->primaryTileset, this->secondaryTileset);
+}
+
 void MetatileSelector::mousePressEvent(QGraphicsSceneMouseEvent *event) {
+    if (!shouldAcceptEvent(event)) return;
     SelectablePixmapItem::mousePressEvent(event);
     this->updateSelectedMetatiles();
     emit selectedMetatilesChanged();
 }
 
 void MetatileSelector::mouseMoveEvent(QGraphicsSceneMouseEvent *event) {
+    if (!shouldAcceptEvent(event)) return;
     SelectablePixmapItem::mouseMoveEvent(event);
     this->updateSelectedMetatiles();
 
@@ -108,6 +116,7 @@ void MetatileSelector::mouseMoveEvent(QGraphicsSceneMouseEvent *event) {
 }
 
 void MetatileSelector::mouseReleaseEvent(QGraphicsSceneMouseEvent *event) {
+    if (!shouldAcceptEvent(event)) return;
     SelectablePixmapItem::mouseReleaseEvent(event);
     this->updateSelectedMetatiles();
     emit selectedMetatilesChanged();
@@ -147,9 +156,7 @@ uint16_t MetatileSelector::getMetatileId(int x, int y) {
 }
 
 QPoint MetatileSelector::getMetatileIdCoords(uint16_t metatileId) {
-    if (metatileId >= Project::getNumMetatilesTotal()
+    if (!Tileset::metatileIsValid(metatileId, this->primaryTileset, this->secondaryTileset))
-       || (metatileId < Project::getNumMetatilesPrimary() && metatileId >= this->primaryTileset->metatiles->length())
-       || (metatileId < Project::getNumMetatilesTotal() && metatileId >= Project::getNumMetatilesPrimary() + this->secondaryTileset->metatiles->length()))
     {
         // Invalid metatile id.
         return QPoint(0, 0);