From 2bc88768b6951ce4fd4b3b1a634919b02f03ded6 Mon Sep 17 00:00:00 2001
From: Filippo Scognamiglio <flscogna@gmail.com>
Date: Tue, 20 Jan 2015 00:57:23 +0100
Subject: [PATCH] Reduce minimum scaling value and fix aliasing issues with
 small fonts and rasterization.

---
 app/qml/ApplicationSettings.qml | 11 ++++++++---
 app/qml/SettingsTerminalTab.qml |  4 ++--
 app/qml/ShaderTerminal.qml      | 15 +++++++++++++--
 app/qml/utils.js                |  8 +++++++-
 4 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/app/qml/ApplicationSettings.qml b/app/qml/ApplicationSettings.qml
index c3d4583..1b4fd8b 100644
--- a/app/qml/ApplicationSettings.qml
+++ b/app/qml/ApplicationSettings.qml
@@ -26,7 +26,12 @@ import "utils.js" as Utils
 QtObject{
     property string version: "1.0.0 RC1"
 
-    // GENERAL SETTINGS ///////////////////////////////////////////////////
+    // STATIC CONSTANTS ////////////////////////////////////////////////////////
+
+    readonly property real minimumFontScaling: 0.25
+    readonly property real maximumFontScaling: 2.50
+
+    // GENERAL SETTINGS ///////////////////////////////////////////////////////
 
     property bool fullscreen: false
     property bool showMenubar: true
@@ -114,12 +119,12 @@ QtObject{
     }
 
     function incrementScaling(){
-        fontScaling = Math.min(fontScaling + 0.05, 2.50);
+        fontScaling = Math.min(fontScaling + 0.05, maximumFontScaling);
         handleFontChanged();
     }
 
     function decrementScaling(){
-        fontScaling = Math.max(fontScaling - 0.05, 0.50);
+        fontScaling = Math.max(fontScaling - 0.05, minimumFontScaling);
         handleFontChanged();
     }
 
diff --git a/app/qml/SettingsTerminalTab.qml b/app/qml/SettingsTerminalTab.qml
index ae0e719..32f458f 100644
--- a/app/qml/SettingsTerminalTab.qml
+++ b/app/qml/SettingsTerminalTab.qml
@@ -66,8 +66,8 @@ Tab{
                         stepSize: 0.05
                         enabled: false // Another trick to fix initial bad behavior.
                         Component.onCompleted: {
-                            minimumValue = 0.5;
-                            maximumValue = 2.5;
+                            minimumValue = appSettings.minimumFontScaling;
+                            maximumValue = appSettings.maximumFontScaling;
                             value = appSettings.fontScaling;
                             enabled = true;
                         }
diff --git a/app/qml/ShaderTerminal.qml b/app/qml/ShaderTerminal.qml
index aa024b0..f3478e2 100644
--- a/app/qml/ShaderTerminal.qml
+++ b/app/qml/ShaderTerminal.qml
@@ -21,6 +21,8 @@
 import QtQuick 2.2
 import QtGraphicalEffects 1.0
 
+import "utils.js" as Utils
+
 ShaderEffect {
     property ShaderEffectSource source
     property ShaderEffectSource blurredSource
@@ -56,6 +58,12 @@ ShaderEffect {
 
     property real screen_brightness: appSettings.brightness * 1.5 + 0.5
 
+    // This is the average value of the abs(sin) function. Needed to avoid aliasing.
+    readonly property real absSinAvg: 0.63661828335466886
+    property size rasterizationSmooth: Qt.size(
+                                           Utils.clamp(2.0 * virtual_resolution.width / width, 0.0, 1.0),
+                                           Utils.clamp(2.0 * virtual_resolution.height / height, 0.0, 1.0))
+
     property real dispX
     property real dispY
     property size virtual_resolution
@@ -153,6 +161,7 @@ ShaderEffect {
         uniform lowp float screen_brightness;
 
         uniform highp vec2 virtual_resolution;
+        uniform highp vec2 rasterizationSmooth;
         uniform highp float dispX;
         uniform highp float dispY;" +
 
@@ -198,9 +207,11 @@ ShaderEffect {
             highp float result = 1.0;" +
 
            (appSettings.rasterization != appSettings.no_rasterization ?
-               "result *= abs(sin(coords.y * virtual_resolution.y * "+Math.PI+"));" : "") +
+               "float val = abs(sin(coords.y * virtual_resolution.y * "+Math.PI+"));
+                result *= mix(val, " + absSinAvg + ", rasterizationSmooth.y);" : "") +
            (appSettings.rasterization == appSettings.pixel_rasterization ?
-               "result *= abs(sin(coords.x * virtual_resolution.x * "+Math.PI+"));" : "") + "
+               "val = abs(sin(coords.x * virtual_resolution.x * "+Math.PI+"));
+                result *= mix(val, " + absSinAvg + ", rasterizationSmooth.x);" : "") + "
 
            return result;
         }
diff --git a/app/qml/utils.js b/app/qml/utils.js
index b7daf2d..ba8ae04 100644
--- a/app/qml/utils.js
+++ b/app/qml/utils.js
@@ -1,5 +1,11 @@
 .pragma library
-
+function clamp(x, min, max) {
+    if (x <= min)
+        return min;
+    if (x >= max)
+        return max;
+    return x;
+}
 function lint(a, b, t) {
     return (1 - t) * a + (t) * b;
 }