website: dynamic metrics update

8 files changed, 161 insertions, 36 deletions

diff --git a/docs/_includes/preload-font-files.html b/docs/_includes/preload-font-files.html
index 9533ce0b5..34847f426 100644
--- a/docs/_includes/preload-font-files.html
+++ b/docs/_includes/preload-font-files.html
@@ -1,2 +1,2 @@
-<link rel="preload" href="font-files/Inter-upright.var.woff2?v=3.3" as="font" type="font/woff2" crossorigin>
-    <link rel="preload" href="font-files/Inter-italic.var.woff2?v=3.3" as="font" type="font/woff2" crossorigin>
\ No newline at end of file
+<link rel="preload" href="/font-files/Inter-upright.var.woff2?v=3.3" as="font" type="font/woff2" crossorigin>
+    <link rel="preload" href="/font-files/Inter-italic.var.woff2?v=3.3" as="font" type="font/woff2" crossorigin>
\ No newline at end of file
diff --git a/docs/dynmetrics/index.css b/docs/dynmetrics/index.css
index f4328c6b2..cd9fb98cf 100644
--- a/docs/dynmetrics/index.css
+++ b/docs/dynmetrics/index.css
@@ -75,6 +75,7 @@ formula.code {
     outline: none;
     margin-right: 50px;
     margin-bottom: 50px;
+    min-width: 50px;
   }
   .samples .sample > * {
     display: block;
diff --git a/docs/dynmetrics/index.html b/docs/dynmetrics/index.html
index 9b5022c3f..e43be7c9c 100644
--- a/docs/dynmetrics/index.html
+++ b/docs/dynmetrics/index.html
@@ -32,7 +32,7 @@ endfor
     yourself with typography, but Inter Dynamic Metrics provides guidelines
     for how to best use Inter.
     You simply provide the optical font size,
-    and the tracking and leading is calculated for you through the following
+    and the tracking and line height is calculated for you through the following
     formula:
   </p>
   <p>
@@ -42,12 +42,12 @@ endfor
       <const title="Base of natural logarithm; ≈2.718">e</const><sup>(<const>c</const> × <const>z</const>)</sup>
     </formula>
     <formula>
-      leading = round(<num data-binding="var-l">1.4</num> × <const>z</const>)
+      line height = <num data-binding="var-l">1.4</num> × <const>z</const>
     </formula>
     <formula title="Values for Inter">
-      <g><const title="Constant a">a</const> = <num data-binding="var-a">-0.016</num></g> &nbsp;&nbsp;
-      <g><const title="Constant b">b</const> = <num data-binding="var-b">0.21</num></g> &nbsp;&nbsp;
-      <g><const title="Constant c">c</const> = <num data-binding="var-c">-0.18</num></g> &nbsp;&nbsp;
+      <g><const title="Constant a">a</const> = <num data-binding="var-a">-0.02</num></g> &nbsp;&nbsp;
+      <g><const title="Constant b">b</const> = <num data-binding="var-b">0.205</num></g> &nbsp;&nbsp;
+      <g><const title="Constant c">c</const> = <num data-binding="var-c">-0.175</num></g> &nbsp;&nbsp;
       <g><const>z</const> = font size</g>
     </formula>
   </p>
@@ -194,24 +194,24 @@ function parseValues(s) {
 }
 
 setIdealValues({
-  // 2018-09-28
-  6:   0.054,
-  7:   0.042,
-  8:   0.033,
-  9:   0.025,
-  10:  0.018,
-  11:  0.012,
-  12:  0.008,
-  13:  0.004,
-  14:  0,
-  15: -0.002,
+  6:   0.021,
+  7:   0.017,
+  8:   0.013,
+  9:   0.01,
+  10:  0.007,
+  11:  0.005,
+  12:  0.002,
+  13:  0,
+  14: -0.002,
+  15: -0.004,
   16: -0.005,
   17: -0.007,
   18: -0.008,
-  20: -0.011,
-  24: -0.014,
+  20: -0.01,
+  24: -0.013,
   30: -0.016,
-  40: -0.017,
+  40: -0.02,
+  80: -0.02,
 })
 
 
@@ -222,7 +222,9 @@ setIdealValues({
 // var a = -0.015, b = 0.283, c = -0.23; // di=0.00221 on set-2018-02-18
 // var a = -0.0149, b = 0.298, c = -0.23; // di=0.000484 on set-2018-02-19
 // var a = -0.018, b = 0.21, c = -0.18; // di=0.000532 on set-2018-02-20
-var a = -0.017, b = 0.202, c = -0.175; // di=0.000247 on 2018-09-28
+// var a = -0.017, b = 0.202, c = -0.175; // 2018-09-28
+var a = -0.02, b = 0.0755, c = -0.102 // 2019-02-02
+
 
 var l = 1.4
 
@@ -238,10 +240,6 @@ function _InterDynamicTracking(fontSize, weightClass) {
   // See https://gist.github.com/rsms/8efdbca5f8145a584ed08a7c3d6e5788
   //
   return a + b * Math.pow(Math.E, c * fontSize)
-  // [6 - 38]  0.05798 .. -0.01099  (midpoint = 12.533)
-  //
-  // y = 0.025 - (ln(x) * 0.01)
-  // return 0.025 - Math.log(fontSize) * 0.01
 }
 
 
@@ -335,6 +333,11 @@ Sample.prototype.cssProperties = function() {
   ]
 }
 
+Sample.prototype.setText = function(text) {
+  this.contentEl.innerText = text
+  this.render()
+}
+
 Sample.prototype.render = function() {
   this.style.fontSize = this.fontSize + 'px'
   this.style.letterSpacing = this.tracking + 'em'
@@ -393,6 +396,7 @@ function initSamples() {
   samples.push(new Sample(24))
   samples.push(new Sample(30))
   samples.push(new Sample(40))
+  samples.push(new Sample(80))
 
   // connect focus events
   var onSampleReceivedFocus = function() { setSelectedSample(this) }
diff --git a/docs/index.html b/docs/index.html
index 5ec838edc..edbd10835 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -100,8 +100,8 @@ html { font-family: 'Inter', sans-serif; }
 <div class="row"><div>
   <h2><a id="weights" href="#weights">Weights & Styles</a></h2>
   <p>
-  There are six weights, each with italic counterparts,
-  making a total of 12 styles.
+  There are nine weights, each with italic counterparts,
+  making a total of 18 styles.
   </p>
   <img src="res/weights-and-styles.svg" style="opacity:0.88;width:100%;display:block;margin:3em 0 3em 0">
 </div></div>
@@ -564,10 +564,10 @@ var unitEl = $('#dynmet-unit')
 
 var unitFormatters = [
   ['em', 'em', function(fontSize, tracking) {
-    return tracking.toFixed(3)
+    return tracking.toFixed(3).replace(/(?:\.000|0+)$/, '')
   }],
   ['px', 'px', function(fontSize, tracking) {
-    return (fontSize * tracking).toFixed(1)
+    return (fontSize * tracking).toFixed(2).replace(/(?:\.00|0+)$/, '')
   }],
   ['%', 'percent', function(fontSize, tracking) {
     return (tracking * 100).toFixed(1)
diff --git a/docs/res/base.js b/docs/res/base.js
index ba858b62e..40188360e 100644
--- a/docs/res/base.js
+++ b/docs/res/base.js
@@ -81,8 +81,8 @@ var HUDNotification = {
 // the compensating tracking in EM.
 //
 function InterDynamicTracking(fontSize) {
+  var a = -0.02, b = 0.0755, c = -0.102;
   // tracking = a + b * e ^ (c * fontSize)
-  var a = -0.017, b = 0.202, c = -0.175;
   return a + b * Math.pow(Math.E, c * fontSize)
 }
 
diff --git a/docs/samples/index.css b/docs/samples/index.css
index 6114ae255..a1234d8cc 100644
--- a/docs/samples/index.css
+++ b/docs/samples/index.css
@@ -8,22 +8,33 @@ body {
   text-align:center;
 }
 
+.live > hr {
+  margin: 3rem 0 4rem 0;
+  background: black;
+  height: 2px;
+  border: none;
+}
+
 livesample {
   display: block;
   color: #111;
   outline: none;
-  /*padding-left: 20px;
+  margin-top: 1rem;
+  margin-bottom: 1rem;
+}
+
+/*livesample {
+  padding-left: 20px;
   border-left: 2px solid transparent;
-  margin-left:-22px;*/
-  margin-top: 1em;
-  margin-bottom: 1.6em;
+  margin-left:-22px;
 }
 livesample:hover {
   border-left-color: rgb(3, 102, 214);
 }
-/*livesample:focus {
+livesample:focus {
   border-left-color: #eee;
 }*/
+
 livesample > p {
   margin-top: 0;
 }
diff --git a/docs/samples/index.html b/docs/samples/index.html
index 88f389c88..3784fcccb 100644
--- a/docs/samples/index.html
+++ b/docs/samples/index.html
@@ -28,6 +28,17 @@ endfor
 
 <div class="row"><div>
   <div class="live">
+    <livesample data-ctxedit="sample-x1"
+      style="font-size:80px;line-height:1.0" contenteditable>
+      Interfacing mechanisms
+    </livesample>
+
+    <livesample data-ctxedit="sample-x2"
+      style="font-weight:100;font-size:80px;line-height:1.2" contenteditable>
+      XP–45 / vessel
+    </livesample>
+
+    <hr>
 
     <livesample contenteditable class="s1" data-ctxedit="sample1">
       Fabulous typography encountering spring
diff --git a/misc/dynmet-search.js b/misc/dynmet-search.js
new file mode 100644
index 000000000..33189b8ea
--- /dev/null
+++ b/misc/dynmet-search.js
@@ -0,0 +1,98 @@
+//
+// Program that searches for optimal a,b,c values for dynamic metrics.
+//
+// Provide ideal tracking values for font sizes in idealTracking and start
+// this program. It will run forever and print to stdout when it finds
+// better a,b,c values that brings you closer to the ideal values.
+//
+// These are the initial a,b,c values. (Update if you find better values.)
+let a = -0.02, b = 0.0755, c = -0.1021 // 0.00092
+//
+// These are the ideal tracking values.
+let idealTracking = {
+  // 6:   0.05,
+  // 7:   0.04,
+  // 8:   0.03,
+  9:   0.01,
+  // 10:  0.015,
+  11:  0.005,
+  12:  0.0025,
+  13:  0,
+  // 14:  0,
+  // 15: -0.002,
+  16: -0.005,
+  // 17: -0.008,
+  18: -0.01,
+  // 20: -0.014,
+  // 24: -0.016,
+  // 30: -0.019,
+  40: -0.022,
+}
+
+
+let idealTrackingList = Object.keys(idealTracking).map(fontSize =>
+  [fontSize, idealTracking[fontSize]]
+)
+
+function sample(a, b, c) {
+  let idealDist = 0.0
+  for (let [fontSize, idealTracking] of idealTrackingList) {
+
+    let tracking = a + b * Math.pow(Math.E, c * fontSize)
+
+    let dist = Math.abs(tracking - idealTracking)
+
+    idealDist += dist
+    // console.log(`${fontSize} d=${tracking - idealTracking} d'=${dist}`)
+  }
+  // console.log(`idealDist=${idealDist}`)
+  return idealDist / idealTrackingList.length
+}
+
+const prec = 4  // precision
+let bestConstants = { a, b, c }
+let isneg = {
+  a: a < 0,
+  b: b < 0,
+  c: c < 0,
+}
+let bestDistance = sample(a, b, c)
+
+console.log(
+  '------------------------------------------------------------------\n' +
+  `| Started at ${(new Date()).toLocaleString()} with initial values:\n` +
+  `|   a = ${bestConstants.a}, b = ${bestConstants.b},` +
+  ` c = ${bestConstants.c} // D ${bestDistance.toFixed(5)}\n` +
+  `| Ctrl-C to end.\n` +
+  '------------------------------------------------------------------'
+)
+
+function logNewBest() {
+  console.log(
+    `new best: a = ${a.toFixed(prec)}, b = ${b.toFixed(prec)}, c = ${c.toFixed(prec)} // D ${bestDistance.toFixed(5)}`
+  )
+}
+
+while (true) {
+  // a = parseFloat((bestConstants.a * ((Math.random() * 2.0) - 1.0)).toFixed(prec))
+  // b = parseFloat((bestConstants.b * ((Math.random() * 2.0) - 1.0)).toFixed(prec))
+  // c = parseFloat((bestConstants.c * ((Math.random() * 2.0) - 1.0)).toFixed(prec))
+
+  let a2 = bestConstants.a * ((Math.random() * 2.0) - 1.0)
+  let b2 = bestConstants.b * ((Math.random() * 2.0) - 1.0)
+  let c2 = bestConstants.c * ((Math.random() * 2.0) - 1.0)
+
+  if (isneg.a) { if (a2 > 0) { a2 = a } } else if (a2 < 0) { a2 = a }
+  if (isneg.b) { if (b2 > 0) { b2 = b } } else if (b2 < 0) { b2 = b }
+  if (isneg.c) { if (c2 > 0) { c2 = c } } else if (c2 < 0) { c2 = c }
+
+  a = a2
+  b = b2
+  c = c2
+
+  let dist = sample(a, b, c)
+  if (dist < bestDistance) {
+    bestDistance = dist
+    logNewBest()
+  }
+}