show recipes visually instead of describing them in text

src/ui/RecipeLineRow.cpp

@@ -0,0 +1,140 @@
+#include "RecipeLineRow.h"
+
+#include <QHBoxLayout>
+#include <QLabel>
+#include <QLayoutItem>
+#include <QPixmap>
+
+#include "BuildingIconCache.h"
+#include "ItemIconCache.h"
+
+namespace
+{
+
+// Size the items' colored squares and the building's chip are drawn at on a line, in
+// device-independent pixels. Larger than the artwork they carry, which the square
+// insets (REQ-UI-ITEM-ICON).
+const int kIconSizePx = 18;
+
+// Adds a freshly built label to the line and shows it.
+//
+// The show is what makes it count: a widget created under an already-visible parent
+// starts hidden, and a layout treats a hidden item as empty, so an unshown label would
+// add nothing to the size hint the surrounding widget measures itself against as soon
+// as this returns.
+void addAndShow(QHBoxLayout* layout, QLabel* label)
+{
+    layout->addWidget(label);
+    label->show();
+}
+
+}  // namespace
+
+
+RecipeLineRow::RecipeLineRow(ItemIconCache* itemIcons, BuildingIconCache* buildingIcons,
+                             QWidget* parent)
+    : QWidget(parent)
+    , m_itemIcons(itemIcons)
+    , m_buildingIcons(buildingIcons)
+{
+    m_layout = new QHBoxLayout(this);
+    m_layout->setContentsMargins(0, 0, 0, 0);
+    m_layout->setSpacing(4);
+
+    hide();
+}
+
+void RecipeLineRow::setLine(const Spec& spec)
+{
+    if (spec.isEmpty())
+    {
+        // Forgotten as well as hidden, so re-selecting the same recipe later is seen as
+        // a change and shows the row again.
+        m_spec = Spec();
+        hide();
+        return;
+    }
+    if (spec == m_spec)
+    {
+        return;
+    }
+
+    m_spec = spec;
+    rebuild(spec);
+    show();
+}
+
+void RecipeLineRow::rebuild(const Spec& spec)
+{
+    while (QLayoutItem* item = m_layout->takeAt(0))
+    {
+        if (item->widget())
+        {
+            item->widget()->deleteLater();
+        }
+        delete item;
+    }
+
+    // The building the recipe runs in, where the line has to distinguish one producer
+    // from another (REQ-UI-ITEM-TOOLTIP). A building with no chip file leaves the icon
+    // off, as everywhere else (REQ-UI-BUILD-ICON).
+    if (spec.building.has_value() && m_buildingIcons != nullptr)
+    {
+        const QPixmap chip =
+            m_buildingIcons->getChip(buildingTypeId(*spec.building), kIconSizePx);
+        if (!chip.isNull())
+        {
+            QLabel* chipLabel = new QLabel(this);
+            chipLabel->setPixmap(chip);
+            addAndShow(m_layout, chipLabel);
+        }
+    }
+    if (!spec.name.isEmpty())
+    {
+        addAndShow(m_layout, new QLabel(spec.name, this));
+    }
+
+    addAmounts(spec.inputs);
+    if (!spec.inputs.empty() && !spec.outputs.empty())
+    {
+        const QChar rightArrow(0x2192);  // U+2192 RIGHTWARDS ARROW
+        addAndShow(m_layout, new QLabel(QString(rightArrow), this));
+    }
+    addAmounts(spec.outputs);
+
+    if (spec.durationSeconds.has_value() && *spec.durationSeconds > 0.0)
+    {
+        const QChar middleDot(0x00B7);  // U+00B7 MIDDLE DOT
+        const QString time = spec.durationIsAddition
+            ? tr("+%1 s").arg(*spec.durationSeconds, 0, 'f', 1)
+            : tr("%1 s").arg(*spec.durationSeconds, 0, 'f', 1);
+        addAndShow(m_layout, new QLabel(
+            QStringLiteral("%1 %2").arg(middleDot).arg(time), this));
+    }
+    m_layout->addStretch(1);
+}
+
+void RecipeLineRow::addAmounts(const std::vector<Amount>& amounts)
+{
+    for (const Amount& entry : amounts)
+    {
+        // The item's icon on its colored square (REQ-UI-ITEM-ICON). A missing icon file
+        // is not an error: the square stands alone then, and only an item with no square
+        // either falls back to its id in text.
+        const QPixmap icon = (m_itemIcons != nullptr)
+            ? m_itemIcons->getSquarePixmap(entry.itemId, kIconSizePx)
+            : QPixmap();
+        if (!icon.isNull())
+        {
+            QLabel* iconLabel = new QLabel(this);
+            iconLabel->setPixmap(icon);
+            addAndShow(m_layout, iconLabel);
+        }
+        else
+        {
+            addAndShow(m_layout,
+                       new QLabel(QString::fromStdString(entry.itemId), this));
+        }
+        addAndShow(m_layout, new QLabel(QString::number(entry.amount), this));
+    }
+}