From 42f2f6419bbff03931654e52a885b0600eec9b9b Mon Sep 17 00:00:00 2001
From: sam-anthony <samanthony6@protonmail.com>
Date: Sat, 26 Mar 2022 16:30:43 -0230
Subject: pressure ratio

---
 main.go        | 16 ++++++++++++++++
 pressure.go    |  4 ++++
 temperature.go |  2 +-
 ui.go          | 50 ++++++++++++++++++++++++++++++++++++++++++--------
 4 files changed, 63 insertions(+), 9 deletions(-)

diff --git a/main.go b/main.go
index 653fd61..80d0e03 100644
--- a/main.go
+++ b/main.go
@@ -54,6 +54,21 @@ var (
 	selectedPressureUnit = defaultPressureUnitIndex
 )
 
+var pressureRatio [numPoints]float32
+
+func pressureRatioAt(point int) float32 {
+	u := pascal
+	m := manifoldPressure[point].asUnit(u)
+	a := atmosphericPressure().asUnit(u)
+	return m / a
+}
+
+func init() {
+	for i := 0; i < numPoints; i++ {
+		pressureRatio[i] = pressureRatioAt(i)
+	}
+}
+
 func loop() {
 	g.SingleWindow().Layout(
 		engineDisplacementRow(),
@@ -63,6 +78,7 @@ func loop() {
 				volumetricEfficiencyRow(),
 				intakeAirTemperatureRow(),
 				manifoldPressureRow(),
+				pressureRatioRow(),
 			).
 			Columns(
 				g.TableColumn("Parameter"),
diff --git a/pressure.go b/pressure.go
index f486552..a6665dc 100644
--- a/pressure.go
+++ b/pressure.go
@@ -52,3 +52,7 @@ func (p pressure) asUnit(u pressureUnit) float32 {
 	pa := p.val * float32(p.unit) // Convert to pascals.
 	return pa / float32(u)        // Convert to desired unit.
 }
+
+func atmosphericPressure() pressure {
+	return pressure{1, bar}
+}
diff --git a/temperature.go b/temperature.go
index 89cb1ba..7562ca7 100644
--- a/temperature.go
+++ b/temperature.go
@@ -64,7 +64,7 @@ func (t temperature) asUnit(u temperatureUnit) (float32, error) {
 	case kelvin:
 		return c + 272.15, nil
 	case fahrenheit:
-		return c * (9.0 / 5.0) + 32.0, nil
+		return c*(9.0/5.0) + 32.0, nil
 	default:
 		return 0, errors.New(fmt.Sprintf("invalid temperatureUnit: '%v'", u))
 	}
diff --git a/ui.go b/ui.go
index 57765a3..d72fec4 100644
--- a/ui.go
+++ b/ui.go
@@ -1,6 +1,9 @@
 package main
 
-import g "github.com/AllenDang/giu"
+import (
+	g "github.com/AllenDang/giu"
+	"strconv"
+)
 
 func engineDisplacementRow() *g.RowWidget {
 	return g.Row(
@@ -93,18 +96,49 @@ func manifoldPressureRow() *g.TableRowWidget {
 				u, err := pressureUnitFromString(s)
 				check(err)
 
-				for i := range manifoldPressure {
+				for i := 0; i < numPoints; i++ {
 					manifoldPressure[i] = pressure{
 						manifoldPressure[i].asUnit(u),
 						u,
 					}
 				}
 			}),
-		g.InputFloat(&manifoldPressure[0].val).Format("%.2f"),
-		g.InputFloat(&manifoldPressure[1].val).Format("%.2f"),
-		g.InputFloat(&manifoldPressure[2].val).Format("%.2f"),
-		g.InputFloat(&manifoldPressure[3].val).Format("%.2f"),
-		g.InputFloat(&manifoldPressure[4].val).Format("%.2f"),
-		g.InputFloat(&manifoldPressure[5].val).Format("%.2f"),
+		g.InputFloat(&manifoldPressure[0].val).Format("%.2f").
+			OnChange(func() {
+				pressureRatio[0] = pressureRatioAt(0)
+			}),
+		g.InputFloat(&manifoldPressure[1].val).Format("%.2f").
+			OnChange(func() {
+				pressureRatio[1] = pressureRatioAt(1)
+			}),
+		g.InputFloat(&manifoldPressure[2].val).Format("%.2f").
+			OnChange(func() {
+				pressureRatio[2] = pressureRatioAt(2)
+			}),
+		g.InputFloat(&manifoldPressure[3].val).Format("%.2f").
+			OnChange(func() {
+				pressureRatio[3] = pressureRatioAt(3)
+			}),
+		g.InputFloat(&manifoldPressure[4].val).Format("%.2f").
+			OnChange(func() {
+				pressureRatio[4] = pressureRatioAt(4)
+			}),
+		g.InputFloat(&manifoldPressure[5].val).Format("%.2f").
+			OnChange(func() {
+				pressureRatio[5] = pressureRatioAt(5)
+			}),
+	)
+}
+
+func pressureRatioRow() *g.TableRowWidget {
+	return g.TableRow(
+		g.Label("Pressure Ratio"),
+		g.Label(""),
+		g.Label(strconv.FormatFloat(float64(pressureRatio[0]), 'f', 1, 32)),
+		g.Label(strconv.FormatFloat(float64(pressureRatio[1]), 'f', 1, 32)),
+		g.Label(strconv.FormatFloat(float64(pressureRatio[2]), 'f', 1, 32)),
+		g.Label(strconv.FormatFloat(float64(pressureRatio[3]), 'f', 1, 32)),
+		g.Label(strconv.FormatFloat(float64(pressureRatio[4]), 'f', 1, 32)),
+		g.Label(strconv.FormatFloat(float64(pressureRatio[5]), 'f', 1, 32)),
 	)
 }
-- 
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