From 88a94c7d665fd3b8c6e181fa4b71ecd7a85c032b Mon Sep 17 00:00:00 2001
From: Explorer09 <explorer09@gmail.com>
Date: Thu, 15 Feb 2024 14:52:33 +0800
Subject: [PATCH] makeDetailsMask() prevTopPoint arg (q20)

---
 Meter.c | 27 +++++++++++++--------------
 Meter.h |  1 -
 2 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/Meter.c b/Meter.c
index ab2ec19550..8a25bbb25c 100644
--- a/Meter.c
+++ b/Meter.c
@@ -498,7 +498,7 @@ static void GraphMeterMode_addItemAdjStack(GraphColorAdjStack* stack, double sca
    stack->nItems++;
 }
 
-static uint16_t GraphMeterMode_makeDetailsMask(const GraphColorComputeState* prev, const GraphColorComputeState* new, double rem, int blanksAtTopCell) {
+static uint16_t GraphMeterMode_makeDetailsMask(const GraphColorComputeState* prev, const GraphColorComputeState* new, double prevTopPoint, double rem, int blanksAtTopCell) {
    assert(new->nCellsPainted > prev->nCellsPainted);
    assert(rem >= 0.0);
    assert(rem < 1.0);
@@ -513,17 +513,15 @@ static uint16_t GraphMeterMode_makeDetailsMask(const GraphColorComputeState* pre
       assert(blanksAtTopCell < 8);
       blanksAtEnd = (uint8_t)blanksAtTopCell;
       roundsUpInAscii = true;
-   } else if (prev->nCellsPainted == 0 || prev->topPoint <= prev->nCellsPainted) {
+   } else if (prev->nCellsPainted == 0 || prevTopPoint <= prev->nCellsPainted || rem <= 0.0) {
       blanksAtEnd = (uint8_t)maxBlanks % 8;
-   } else if (new->nCellsPainted > new->topPoint) {
-      assert(new->nCellsPainted - new->topPoint < 1.0);
-      assert(rem > 0.0);
+   } else {
       // Unlike other conditions, this one rounds to nearest for visual reason.
       // In case of a tie, display the dot at lower position of the graph,
       // i.e. MSB of the "details" data.
 
-      double distance = new->topPoint - (new->nCellsPainted - 1);
-      distance = distance - rem * 0.5;
+      double distance = prevTopPoint - prev->nCellsPainted;
+      distance = distance + rem * 0.5;
 
       // Tiebreaking direction that may be needed in the ASCII display mode.
       roundsUpInAscii = distance > 0.5;
@@ -531,9 +529,11 @@ static uint16_t GraphMeterMode_makeDetailsMask(const GraphColorComputeState* pre
 
       double fraction = (uint8_t)numDots % 2 == 0 ? 0.5 : 0.0;
       distance = ceil(distance * 8.0 - fraction);
-      blanksAtEnd = 8.0 - distance - (uint8_t)numDots / 2;
-   } else {
-      blanksAtEnd = 0;
+      if (8.0 - distance - (uint8_t)numDots / 2 > 0) {
+         blanksAtEnd = 8.0 - distance - (uint8_t)numDots / 2;
+      } else {
+         blanksAtEnd = 0;
+      }
    }
    assert(blanksAtEnd < 8);
 
@@ -646,7 +646,6 @@ static void GraphMeterMode_computeColors(Meter* this, const GraphDrawContext* co
 
    GraphColorComputeState restart = {
       .valueSum = 0.0,
-      .topPoint = 0.0,
       .nCellsPainted = 0,
       .nItemsPainted = 0
    };
@@ -701,7 +700,6 @@ static void GraphMeterMode_computeColors(Meter* this, const GraphDrawContext* co
             assert(new.valueSum < DBL_MAX || prev.valueSum + value >= DBL_MAX);
          }
 
-         new.topPoint = (new.valueSum / scaledTotal) * (double)(int)graphHeight;
          double area = (value / scaledTotal) * (double)(int)graphHeight;
          assert(area >= 0.0); // "area" can be 0.0 when the division underflows
          double rem = area;
@@ -744,7 +742,7 @@ static void GraphMeterMode_computeColors(Meter* this, const GraphDrawContext* co
             assert(restart.nItemsPainted == prev.nItemsPainted);
 
             if (!rItemIsDetermined) {
-               stack.startPoint = new.topPoint;
+               stack.startPoint = (new.valueSum / scaledTotal) * (double)(int)graphHeight;
                rItemMinCells = nCells;
                rem = 0.0;
             } else if (rItemHasExtraCell) {
@@ -826,8 +824,9 @@ static void GraphMeterMode_computeColors(Meter* this, const GraphDrawContext* co
             rem = (0.125 * dotAlignment);
 
          if (nCells > 0 && new.nCellsPainted <= nCellsToPaint) {
+            double prevTopPoint = (prev.valueSum / scaledTotal) * (double)(int)graphHeight;
             int blanksAtTopCellArg = (new.nCellsPainted == nCellsToPaint) ? (int)blanksAtTopCell : -1;
-            uint16_t mask = GraphMeterMode_makeDetailsMask(&prev, &new, rem, blanksAtTopCellArg);
+            uint16_t mask = GraphMeterMode_makeDetailsMask(&prev, &new, prevTopPoint, rem, blanksAtTopCellArg);
 
             GraphColorCell* cellsStart = &valueStart[firstCellIndex + (size_t)increment * prev.nCellsPainted];
             GraphMeterMode_paintCellsForItem(cellsStart, increment, prev.nItemsPainted, nCells, mask);
diff --git a/Meter.h b/Meter.h
index 4b38956fda..b6d37eb11c 100644
--- a/Meter.h
+++ b/Meter.h
@@ -143,7 +143,6 @@ typedef struct GraphDrawContext_ {
 /* Used in GraphMeterMode_computeColors() subroutines only */
 typedef struct GraphColorComputeState_ {
    double valueSum;
-   double topPoint;
    unsigned int nCellsPainted;
    uint8_t nItemsPainted;
 } GraphColorComputeState;