GUI: Apply clipping only where necessary

Clipping has been disabled globally by taking it out of
Graphics::pushClipArea. Now its name is a little confusing, but it can't
just be changed since it is part of Guichan.

Widgets that do need to clip their children use the new
Graphics::pushClipRect, which pushes a clipping rectangle without
affecting the local coordinates. These are:

* ScrollArea
* TextField
* TabbedArea (scrolling tabs)
* MiniMap

While it might count as a small optimization, I'm actually disabling
clipping because it is not always desired. For example it gets in the
way of rendering the complete ResizeGrip in the Jewelry theme because
that's a child widget.

13 files changed, 123 insertions, 106 deletions

diff --git a/src/graphics.cpp b/src/graphics.cpp
index 72101069..9b8cce83 100644
--- a/src/graphics.cpp
+++ b/src/graphics.cpp
@@ -237,3 +237,20 @@ void Graphics::_endDraw()
 {
     popClipArea();
 }
+
+void Graphics::pushClipRect(const gcn::Rectangle &rect)
+{
+    const gcn::ClipRectangle &carea = mClipStack.top();
+    mClipRects.emplace(rect.x + carea.xOffset,
+                       rect.y + carea.yOffset,
+                       rect.width,
+                       rect.height);
+
+    updateClipRect();
+}
+
+void Graphics::popClipRect()
+{
+    mClipRects.pop();
+    updateClipRect();
+}
diff --git a/src/graphics.h b/src/graphics.h
index 4df63932..4b03023d 100644
--- a/src/graphics.h
+++ b/src/graphics.h
@@ -261,11 +261,19 @@ class Graphics : public gcn::Graphics
             return mColor;
         }
 
+        void pushClipRect(const gcn::Rectangle &rect);
+        void popClipRect();
+
     protected:
+        virtual void updateClipRect() = 0;
+
         int mWidth = 0;
         int mHeight = 0;
         float mScale = 1.0f;
         gcn::Color mColor;
+
+        // Actual clipping rects. Clipping by gcn::Graphics::mClipStack is disabled.
+        std::stack<gcn::Rectangle> mClipRects;
 };
 
 extern Graphics *graphics;
diff --git a/src/gui/itempopup.cpp b/src/gui/itempopup.cpp
index c21f4003..35951331 100644
--- a/src/gui/itempopup.cpp
+++ b/src/gui/itempopup.cpp
@@ -23,7 +23,6 @@
 #include "gui/itempopup.h"
 
 #include "configuration.h"
-#include "graphics.h"
 #include "units.h"
 
 #include "gui/gui.h"
@@ -35,7 +34,6 @@
 #include "utils/gettext.h"
 #include "utils/stringutils.h"
 
-#include "resources/image.h"
 #include "resources/resourcemanager.h"
 #include "resources/theme.h"
 
@@ -139,6 +137,7 @@ void ItemPopup::setNoItem()
 
     mItemDesc->setText(std::string());
     mItemEffect->setText(std::string());
+    mItemWeight->setText(std::string());
 
     setContentSize(mItemName->getWidth(), mItemName->getHeight());
 }
diff --git a/src/gui/minimap.cpp b/src/gui/minimap.cpp
index fc7fddd0..8924bc26 100644
--- a/src/gui/minimap.cpp
+++ b/src/gui/minimap.cpp
@@ -37,6 +37,7 @@
 #include "utils/filesystem.h"
 #include "utils/gettext.h"
 
+#include <algorithm>
 #include <guichan/font.hpp>
 
 Minimap::Minimap():
@@ -136,40 +137,38 @@ void Minimap::draw(gcn::Graphics *graphics)
 {
     Window::draw(graphics);
 
+    if (!mMap)
+        return;
+
+    auto g = static_cast<Graphics*>(graphics);
     const gcn::Rectangle a = getChildrenArea();
 
-    graphics->pushClipArea(a);
+    g->pushClipRect(a); // does actual clipping
+    g->pushClipArea(a); // only applies an offset
+
+    const int tileWidth = mMap->getTileWidth();
+    const int tileHeight = mMap->getTileHeight();
 
     int mapOriginX = 0;
     int mapOriginY = 0;
 
-    if (mMapImage && mMap)
+    if (mMapImage)
     {
         if (mMapImage->getWidth() > a.width ||
             mMapImage->getHeight() > a.height)
         {
             const Vector &p = local_player->getPosition();
-            mapOriginX = (int) (((a.width) / 2) - (int) (p.x * mWidthProportion)
-                         / mMap->getTileWidth());
-            mapOriginY = (int) (((a.height) / 2)
-                         - (int) (p.y * mHeightProportion)
-                         / mMap->getTileHeight());
+            mapOriginX = (a.width / 2) - (int) (p.x * mWidthProportion) / tileWidth;
+            mapOriginY = (a.height / 2) - (int) (p.y * mHeightProportion) / tileHeight;
 
             const int minOriginX = a.width - mMapImage->getWidth();
             const int minOriginY = a.height - mMapImage->getHeight();
 
-            if (mapOriginX < minOriginX)
-                mapOriginX = minOriginX;
-            if (mapOriginY < minOriginY)
-                mapOriginY = minOriginY;
-            if (mapOriginX > 0)
-                mapOriginX = 0;
-            if (mapOriginY > 0)
-                mapOriginY = 0;
+            mapOriginX = std::clamp(mapOriginX, minOriginX, 0);
+            mapOriginY = std::clamp(mapOriginY, minOriginY, 0);
         }
 
-        static_cast<Graphics*>(graphics)->
-            drawImage(mMapImage, mapOriginX, mapOriginY);
+        g->drawImage(mMapImage, mapOriginX, mapOriginY);
     }
 
     for (auto actor : actorSpriteManager->getAll())
@@ -218,16 +217,14 @@ void Minimap::draw(gcn::Graphics *graphics)
         const int offsetWidth = (int) ((dotSize - 1) * mWidthProportion);
         const Vector &pos = being->getPosition();
 
-        if (mMap)
-        {
-            graphics->fillRectangle(gcn::Rectangle(
-                (int) (pos.x * mWidthProportion) / mMap->getTileWidth()
-                + mapOriginX - offsetWidth,
-                (int) (pos.y * mHeightProportion) / mMap->getTileHeight()
-                + mapOriginY - offsetHeight,
-                dotSize, dotSize));
-        }
+        g->fillRectangle(
+            gcn::Rectangle((int) (pos.x * mWidthProportion) / tileWidth + mapOriginX - offsetWidth,
+                           (int) (pos.y * mHeightProportion) / tileHeight + mapOriginY
+                               - offsetHeight,
+                           dotSize,
+                           dotSize));
     }
 
-    graphics->popClipArea();
+    g->popClipArea();
+    g->popClipRect();
 }
diff --git a/src/gui/widgets/scrollarea.cpp b/src/gui/widgets/scrollarea.cpp
index 8ee6692f..c4d55072 100644
--- a/src/gui/widgets/scrollarea.cpp
+++ b/src/gui/widgets/scrollarea.cpp
@@ -134,6 +134,16 @@ void ScrollArea::drawFrame(gcn::Graphics *graphics)
     gui->getTheme()->drawSkin(static_cast<Graphics *>(graphics), SkinType::ScrollArea, state);
 }
 
+void ScrollArea::drawChildren(gcn::Graphics *graphics)
+{
+    auto g = static_cast<Graphics*>(graphics);
+    g->pushClipRect(getChildrenArea());
+
+    gcn::ScrollArea::drawChildren(graphics);
+
+    g->popClipRect();
+}
+
 void ScrollArea::setOpaque(bool opaque)
 {
     mOpaque = opaque;
diff --git a/src/gui/widgets/scrollarea.h b/src/gui/widgets/scrollarea.h
index 314711bf..40f1adc1 100644
--- a/src/gui/widgets/scrollarea.h
+++ b/src/gui/widgets/scrollarea.h
@@ -72,6 +72,11 @@ class ScrollArea : public gcn::ScrollArea
         void drawFrame(gcn::Graphics *graphics) override;
 
         /**
+         * Applies clipping to the contents.
+         */
+        void drawChildren(gcn::Graphics* graphics) override;
+
+        /**
          * Sets whether the widget should draw its background or not.
          */
         void setOpaque(bool opaque);
diff --git a/src/gui/widgets/tabbedarea.cpp b/src/gui/widgets/tabbedarea.cpp
index d9ff9566..fb5436e0 100644
--- a/src/gui/widgets/tabbedarea.cpp
+++ b/src/gui/widgets/tabbedarea.cpp
@@ -21,6 +21,8 @@
 
 #include "gui/widgets/tabbedarea.h"
 
+#include "graphics.h"
+
 #include "gui/widgets/tab.h"
 
 #include <guichan/widgets/container.hpp>
@@ -61,7 +63,12 @@ void TabbedArea::draw(gcn::Graphics *graphics)
     if (mTabs.empty())
         return;
 
+    auto g = static_cast<Graphics*>(graphics);
+    g->pushClipRect(getChildrenArea());
+
     drawChildren(graphics);
+
+    g->popClipRect();
 }
 
 gcn::Widget *TabbedArea::getWidget(const std::string &name) const
@@ -206,9 +213,8 @@ void TabbedArea::updateTabsWidth()
 {
     mTabsWidth = 0;
     for (const auto &[tab, _] : mTabs)
-    {
         mTabsWidth += tab->getWidth();
-    }
+
     updateVisibleTabsWidth();
 }
 
@@ -216,9 +222,7 @@ void TabbedArea::updateVisibleTabsWidth()
 {
     mVisibleTabsWidth = 0;
     for (unsigned int i = mTabScrollIndex; i < mTabs.size(); ++i)
-    {
         mVisibleTabsWidth += mTabs[i].first->getWidth();
-    }
 }
 
 void TabbedArea::adjustTabPositions()
@@ -265,7 +269,7 @@ void TabbedArea::action(const gcn::ActionEvent& actionEvent)
     {
         if (actionEvent.getId() == "shift_left")
         {
-            if (mTabScrollIndex)
+            if (mTabScrollIndex > 0)
                 --mTabScrollIndex;
         }
         else if (actionEvent.getId() == "shift_right")
@@ -282,33 +286,18 @@ void TabbedArea::action(const gcn::ActionEvent& actionEvent)
 void TabbedArea::updateArrowEnableState()
 {
     updateTabsWidth();
-    if (mTabsWidth > getWidth() - 2)
-    {
-        mArrowButton[0]->setVisible(true);
-        mArrowButton[1]->setVisible(true);
-    }
-    else
-    {
-        mArrowButton[0]->setVisible(false);
-        mArrowButton[1]->setVisible(false);
+
+    const bool arrowButtonsVisible = mTabsWidth > getWidth() - 2;
+    mArrowButton[0]->setVisible(arrowButtonsVisible);
+    mArrowButton[1]->setVisible(arrowButtonsVisible);
+
+    if (!arrowButtonsVisible)
         mTabScrollIndex = 0;
-    }
 
-    // Left arrow consistency check
-    if (!mTabScrollIndex)
-        mArrowButton[0]->setEnabled(false);
-    else
-        mArrowButton[0]->setEnabled(true);
+    mArrowButton[0]->setEnabled(mTabScrollIndex > 0);
 
     // Right arrow consistency check
-    if (mVisibleTabsWidth < getWidth() - 2
-        - mArrowButton[0]->getWidth()
-        - mArrowButton[1]->getWidth())
-    {
-        mArrowButton[1]->setEnabled(false);
-    }
-    else
-    {
-        mArrowButton[1]->setEnabled(true);
-    }
+    const int availableWidth = getWidth() - 2 - mArrowButton[0]->getWidth()
+                               - mArrowButton[1]->getWidth();
+    mArrowButton[1]->setEnabled(mVisibleTabsWidth >= availableWidth);
 }
diff --git a/src/gui/widgets/tabbedarea.h b/src/gui/widgets/tabbedarea.h
index c0566faa..558b2696 100644
--- a/src/gui/widgets/tabbedarea.h
+++ b/src/gui/widgets/tabbedarea.h
@@ -36,7 +36,7 @@ class Tab;
 /**
  * A tabbed area, the same as the guichan tabbed area in 0.8, but extended
  */
-class TabbedArea : public gcn::TabbedArea, public gcn::WidgetListener
+class TabbedArea final : public gcn::TabbedArea, public gcn::WidgetListener
 {
     public:
         TabbedArea();
diff --git a/src/gui/widgets/textfield.cpp b/src/gui/widgets/textfield.cpp
index 04955ec8..9f35a5dd 100644
--- a/src/gui/widgets/textfield.cpp
+++ b/src/gui/widgets/textfield.cpp
@@ -53,6 +53,9 @@ void TextField::draw(gcn::Graphics *graphics)
     if (getFrameSize() == 0)
         drawFrame(graphics);
 
+    auto g = static_cast<Graphics *>(graphics);
+    g->pushClipRect(gcn::Rectangle(0, 0, getWidth(), getHeight()));
+
     if (isFocused())
     {
         drawCaret(graphics,
@@ -62,6 +65,8 @@ void TextField::draw(gcn::Graphics *graphics)
     graphics->setColor(Theme::getThemeColor(Theme::TEXT));
     graphics->setFont(getFont());
     graphics->drawText(mText, mPadding - mXScroll, mPadding);
+
+    g->popClipRect();
 }
 
 void TextField::drawFrame(gcn::Graphics *graphics)
diff --git a/src/openglgraphics.cpp b/src/openglgraphics.cpp
index 253cc1d2..51d8cde3 100644
--- a/src/openglgraphics.cpp
+++ b/src/openglgraphics.cpp
@@ -626,14 +626,6 @@ bool OpenGLGraphics::pushClipArea(gcn::Rectangle area)
     glPushMatrix();
     glTranslatef(transX, transY, 0);
 
-    int x = (int) (mClipStack.top().x * mScaleX);
-    int y = (int) ((mHeight - mClipStack.top().y -
-                    mClipStack.top().height) * mScaleY);
-    int width = (int) (mClipStack.top().width * mScaleX);
-    int height = (int) (mClipStack.top().height * mScaleY);
-
-    glScissor(x, y, width, height);
-
     return result;
 }
 
@@ -642,17 +634,6 @@ void OpenGLGraphics::popClipArea()
     Graphics::popClipArea();
 
     glPopMatrix();
-
-    if (mClipStack.empty())
-        return;
-
-    int x = (int) (mClipStack.top().x * mScaleX);
-    int y = (int) ((mHeight - mClipStack.top().y -
-                    mClipStack.top().height) * mScaleY);
-    int width = (int) (mClipStack.top().width * mScaleX);
-    int height = (int) (mClipStack.top().height * mScaleY);
-
-    glScissor(x, y, width, height);
 }
 
 void OpenGLGraphics::setColor(const gcn::Color &color)
@@ -663,6 +644,25 @@ void OpenGLGraphics::setColor(const gcn::Color &color)
     mColorAlpha = (color.a != 255);
 }
 
+void OpenGLGraphics::updateClipRect()
+{
+    if (mClipRects.empty())
+    {
+        glDisable(GL_SCISSOR_TEST);
+        return;
+    }
+
+    const gcn::Rectangle &clipRect = mClipRects.top();
+
+    const int x = (int) (clipRect.x * mScaleX);
+    const int y = (int) ((mHeight - clipRect.y - clipRect.height) * mScaleY);
+    const int width = (int) (clipRect.width * mScaleX);
+    const int height = (int) (clipRect.height * mScaleY);
+
+    glEnable(GL_SCISSOR_TEST);
+    glScissor(x, y, width, height);
+}
+
 void OpenGLGraphics::drawPoint(int x, int y)
 {
     setTexturingAndBlending(false);
diff --git a/src/openglgraphics.h b/src/openglgraphics.h
index 2245938a..b342d9e5 100644
--- a/src/openglgraphics.h
+++ b/src/openglgraphics.h
@@ -115,6 +115,8 @@ class OpenGLGraphics final : public Graphics
     protected:
         void setTexturingAndBlending(bool enable);
 
+        void updateClipRect() override;
+
     private:
         void drawQuadArrayfi(int size);
 
diff --git a/src/sdlgraphics.cpp b/src/sdlgraphics.cpp
index 28907b1e..23336313 100644
--- a/src/sdlgraphics.cpp
+++ b/src/sdlgraphics.cpp
@@ -258,33 +258,21 @@ SDL_Surface *SDLGraphics::getScreenshot()
     return screenshot;
 }
 
-bool SDLGraphics::pushClipArea(gcn::Rectangle area)
+void SDLGraphics::updateClipRect()
 {
-    bool result = Graphics::pushClipArea(area);
-    updateSDLClipRect();
-    return result;
-}
-
-void SDLGraphics::popClipArea()
-{
-    Graphics::popClipArea();
-    updateSDLClipRect();
-}
-
-void SDLGraphics::updateSDLClipRect()
-{
-    if (mClipStack.empty())
+    if (mClipRects.empty())
     {
         SDL_RenderSetClipRect(mRenderer, nullptr);
         return;
     }
 
-    const gcn::ClipRectangle &carea = mClipStack.top();
-    SDL_Rect rect;
-    rect.x = carea.x;
-    rect.y = carea.y;
-    rect.w = carea.width;
-    rect.h = carea.height;
+    const gcn::Rectangle &clipRect = mClipRects.top();
+    const SDL_Rect rect = {
+        clipRect.x,
+        clipRect.y,
+        clipRect.width,
+        clipRect.height
+    };
 
     SDL_RenderSetClipRect(mRenderer, &rect);
 }
diff --git a/src/sdlgraphics.h b/src/sdlgraphics.h
index 806e86f4..2b7635a5 100644
--- a/src/sdlgraphics.h
+++ b/src/sdlgraphics.h
@@ -69,10 +69,6 @@ public:
 
     SDL_Surface *getScreenshot() override;
 
-    bool pushClipArea(gcn::Rectangle area) override;
-
-    void popClipArea() override;
-
     void drawPoint(int x, int y) override;
 
     void drawLine(int x1, int y1, int x2, int y2) override;
@@ -81,8 +77,9 @@ public:
 
     void fillRectangle(const gcn::Rectangle &rectangle) override;
 
-private:
-    void updateSDLClipRect();
+protected:
+    void updateClipRect() override;
 
+private:
     SDL_Renderer *mRenderer = nullptr;
 };