From 38014f4d9930fa8e13019914c2415874294f7342 Mon Sep 17 00:00:00 2001
From: Nishant Mishra <nishant.28@outlook.com>
Date: Thu, 11 Dec 2025 22:26:00 +0530
Subject: [PATCH] feat(stats): add a variable width 1D heatmap visualization

---
 .../components/VariableWidth1DHeatmap.kt      | 117 ++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100644 app/src/main/java/org/nsh07/pomodoro/ui/statsScreen/components/VariableWidth1DHeatmap.kt

diff --git a/app/src/main/java/org/nsh07/pomodoro/ui/statsScreen/components/VariableWidth1DHeatmap.kt b/app/src/main/java/org/nsh07/pomodoro/ui/statsScreen/components/VariableWidth1DHeatmap.kt
new file mode 100644
index 0000000..573b22e
--- /dev/null
+++ b/app/src/main/java/org/nsh07/pomodoro/ui/statsScreen/components/VariableWidth1DHeatmap.kt
@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2025 Nishant Mishra
+ *
+ * This file is part of Tomato - a minimalist pomodoro timer for Android.
+ *
+ * Tomato is free software: you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License as published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * Tomato is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
+ * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with Tomato.
+ * If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package org.nsh07.pomodoro.ui.statsScreen.components
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.MaterialTheme.colorScheme
+import androidx.compose.material3.MaterialTheme.shapes
+import androidx.compose.material3.Surface
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.util.fastForEachIndexed
+import org.nsh07.pomodoro.ui.theme.TomatoTheme
+
+/**
+ * A custom implementation of the 1-Dimensional heatmap plot that varies the width of the cells
+ * instead of the colors. The colors are varied according to the `maxIndex` value passed but they do
+ * NOT correspond to the actual values represented by the cells, and exist for aesthetic reasons
+ * only.
+ */
+@Composable
+fun VariableWidth1DHeatmap(
+    values: List<Long>,
+    modifier: Modifier = Modifier,
+    rankList: List<Int> = remember(values) {
+        val sortedIndices = values.indices.sortedByDescending { values[it] }
+        val ranks = MutableList(values.size) { 0 }
+
+        sortedIndices.forEachIndexed { rank, originalIndex ->
+            ranks[originalIndex] = rank
+        }
+
+        ranks
+    },
+    height: Dp = 40.dp,
+    gap: Dp = 2.dp
+) {
+    val firstNonZeroIndex = remember(values) { values.indexOfFirst { it > 0L } }
+    val lastNonZeroIndex = remember(values) { values.indexOfLast { it > 0L } }
+
+    Row(
+        horizontalArrangement = Arrangement.spacedBy(gap),
+        modifier = modifier
+    ) {
+        values.fastForEachIndexed { index, item ->
+            if (item > 0L) {
+                val shape = when (index) {
+                    firstNonZeroIndex -> shapes.large.copy(
+                        topEnd = shapes.extraSmall.topEnd,
+                        bottomEnd = shapes.extraSmall.bottomEnd
+                    )
+
+                    lastNonZeroIndex -> shapes.large.copy(
+                        topStart = shapes.extraSmall.topStart,
+                        bottomStart = shapes.extraSmall.bottomStart
+                    )
+
+                    else -> shapes.extraSmall
+                }
+                Spacer(
+                    Modifier
+                        .weight(item.toFloat())
+                        .height(height)
+                        .clip(shape)
+                        .background(colorScheme.primaryContainer)
+                        .background(
+                            colorScheme.primary.copy(
+                                (1f - (rankList.getOrNull(index) ?: 0) * 0.1f).coerceAtLeast(0.1f)
+                            )
+                        )
+                )
+            }
+        }
+    }
+}
+
+@Preview
+@Composable
+fun VariableWidth1DHeatmapPreview() {
+    val values = listOf(38L, 190L, 114L, 14L)
+    val rankList = listOf(2, 0, 1, 3)
+    TomatoTheme(dynamicColor = false) {
+        Surface {
+            VariableWidth1DHeatmap(
+                values = values,
+                rankList = rankList,
+                modifier = Modifier.padding(16.dp),
+                height = 40.dp,
+                gap = 2.dp,
+            )
+        }
+    }
+}
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