BasicFontRenderer: Fix various sizing and placement issues

api/Elementa.api

@@ -2892,9 +2892,13 @@ public final class gg/essential/elementa/font/data/AtlasBounds {
 	public final fun copy (FFFF)Lgg/essential/elementa/font/data/AtlasBounds;
 	public static synthetic fun copy$default (Lgg/essential/elementa/font/data/AtlasBounds;FFFFILjava/lang/Object;)Lgg/essential/elementa/font/data/AtlasBounds;
 	public fun equals (Ljava/lang/Object;)Z
+	public final fun getB ()F
 	public final fun getBottom ()F
+	public final fun getL ()F
 	public final fun getLeft ()F
+	public final fun getR ()F
 	public final fun getRight ()F
+	public final fun getT ()F
 	public final fun getTop ()F
 	public fun hashCode ()I
 	public fun toString ()Ljava/lang/String;
@@ -2964,9 +2968,13 @@ public final class gg/essential/elementa/font/data/PlaneBounds {
 	public final fun copy (FFFF)Lgg/essential/elementa/font/data/PlaneBounds;
 	public static synthetic fun copy$default (Lgg/essential/elementa/font/data/PlaneBounds;FFFFILjava/lang/Object;)Lgg/essential/elementa/font/data/PlaneBounds;
 	public fun equals (Ljava/lang/Object;)Z
+	public final fun getB ()F
 	public final fun getBottom ()F
+	public final fun getL ()F
 	public final fun getLeft ()F
+	public final fun getR ()F
 	public final fun getRight ()F
+	public final fun getT ()F
 	public final fun getTop ()F
 	public fun hashCode ()I
 	public fun toString ()Ljava/lang/String;

src/main/kotlin/gg/essential/elementa/font/BasicFontRenderer.kt

@@ -5,7 +5,9 @@ import gg.essential.elementa.UIComponent
 import gg.essential.elementa.constraints.ConstraintType
 import gg.essential.elementa.constraints.resolution.ConstraintVisitor
 import gg.essential.elementa.font.data.Font
+import gg.essential.elementa.font.data.FontInfo
 import gg.essential.elementa.font.data.Glyph
+import gg.essential.elementa.font.data.shrinkGlyphsByHalfAPixel
 import gg.essential.universal.UGraphics
 import gg.essential.universal.UMatrixStack
 import gg.essential.universal.render.UGpuSampler
@@ -15,10 +17,14 @@ import gg.essential.universal.vertex.UBufferBuilder
 import gg.essential.universal.vertex.UVertexConsumer
 import java.awt.Color
 import kotlin.math.max
+import kotlin.math.min
+import kotlin.math.roundToInt
 
 class BasicFontRenderer(
-    private val regularFont: Font
+    regularFont: Font
 ) : FontProvider {
+    private val regularFontInfo = regularFont.fontInfo.shrinkGlyphsByHalfAPixel()
+    private val regularFontTexture by lazy { regularFont.getTexture() }
 
     /* Required by Elementa but unused for this type of constraint */
     override var cachedValue: FontProvider = this
@@ -35,14 +41,15 @@ class BasicFontRenderer(
     }
 
     private fun getStringDimensions(string: String, pointSize: Float): Pair<Float, Float> {
-        var width = 0f
-        var height = 0f
+        var currentX = 0f
+        var top = Float.NEGATIVE_INFINITY
+        var bottom = Float.POSITIVE_INFINITY
 
         /*
             10 point font is the default used in Elementa.
             Adjust the point size based on this font's size.
          */
-        val currentPointSize = pointSize / 10 * regularFont.fontInfo.atlas.size
+        val currentPointSize = pointSize / 10 * regularFontInfo.atlas.size
 
         var i = 0
         while (i < string.length) {
@@ -55,34 +62,34 @@ class BasicFontRenderer(
                 continue
             }
 
-            val glyph = regularFont.fontInfo.glyphs[char.code]
-            if (glyph?.atlasBounds == null) {
+            val glyph = regularFontInfo.glyphs[char.code]
+            if (glyph == null) {
                 i++
                 continue
             }
+
             val planeBounds = glyph.planeBounds
 
             if (planeBounds != null) {
-                height = max((planeBounds.top - planeBounds.bottom) * currentPointSize, height)
+                top = max(top, planeBounds.t)
+                bottom = min(bottom, planeBounds.b)
             }
 
-            //The last character should not have the whitespace to the right of it
-            //Added to the width. Instead, we only add the width of the character
-            val lastCorrection = if (i < string.length - 1) 0 else 1
-
-            //The texture atlas is used here because in the context of this implementation of the font renderer
-            //we do not need or want the full precision the msdf font renderer exports in. Instead, we care about
-            //calculating width based on the texture pixels
-            width += (((glyph.atlasBounds.right - glyph.atlasBounds.left - lastCorrection) / regularFont.fontInfo.atlas.size) * currentPointSize)
-
+            currentX += computeAdvance(regularFontInfo, glyph)
 
             i++
         }
-        return Pair(width, height)
+
+        // undo letter spacing after final letter
+        currentX -= 1 / regularFontInfo.atlas.size
+
+        val width = currentX.coerceAtLeast(0f)
+        val height = if (top.isInfinite() || bottom.isInfinite()) 0f else top - bottom
+        return Pair(width * currentPointSize, height * currentPointSize)
     }
 
     fun getLineHeight(pointSize: Float): Float {
-        return regularFont.fontInfo.metrics.lineHeight * pointSize
+        return regularFontInfo.metrics.lineHeight * pointSize
     }
 
     override fun drawString(
@@ -100,7 +107,7 @@ class BasicFontRenderer(
             val bufferBuilder = UBufferBuilder.create(UGraphics.DrawMode.QUADS, UGraphics.CommonVertexFormats.POSITION_TEXTURE_COLOR)
             drawString(bufferBuilder, matrixStack, string, color, x, y, originalPointSize / 10 * scale, shadow, shadowColor)
             bufferBuilder.build()?.drawAndClose(if (ElementaVersion.atLeastV10Active) PIPELINE2 else PIPELINE) {
-                texture(0, regularFont.getTexture().gpuTextureView, UGpuSampler(
+                texture(0, regularFontTexture.gpuTextureView, UGpuSampler(
                     UGpuSampler.AddressMode.CLAMP_TO_EDGE,
                     UGpuSampler.AddressMode.CLAMP_TO_EDGE,
                     UGpuSampler.FilterMode.NEAREST,
@@ -109,7 +116,7 @@ class BasicFontRenderer(
                 ))
             }
         } else {
-            UGraphics.bindTexture(0, regularFont.getTexture().dynamicGlId)
+            UGraphics.bindTexture(0, regularFontTexture.dynamicGlId)
             val bufferBuilder = UGraphics.getFromTessellator()
             @Suppress("DEPRECATION")
             bufferBuilder.beginWithDefaultShader(UGraphics.DrawMode.QUADS, UGraphics.CommonVertexFormats.POSITION_TEXTURE_COLOR)
@@ -129,14 +136,8 @@ class BasicFontRenderer(
         shadow: Boolean,
         shadowColor: Color?
     ) {
-        val scaledPointSize = scale * regularFont.fontInfo.atlas.size
+        val scaledPointSize = scale * regularFontInfo.atlas.size
 
-        /*
-            Moved one pixel up so that the main body of the text is in
-            the top left of the component. This change keeps text location
-            in the same location as the vanilla font renderer relative to
-            a UIText component.
-         */
         if (shadow) {
             drawStringNow(
                 vertexConsumer,
@@ -146,7 +147,7 @@ class BasicFontRenderer(
                     ((color.rgb and 16579836).shr(2)).or((color.rgb).and(-16777216))
                 ),
                 x + 1,
-                y,
+                y + 1,
                 scaledPointSize,
             )
         }
@@ -156,21 +157,21 @@ class BasicFontRenderer(
             string,
             color,
             x,
-            y - 1,
+            y,
             scaledPointSize,
         )
     }
 
     override fun getBaseLineHeight(): Float {
-        return regularFont.fontInfo.atlas.baseCharHeight
+        return regularFontInfo.atlas.baseCharHeight
     }
 
     override fun getShadowHeight(): Float {
-        return regularFont.fontInfo.atlas.shadowHeight
+        return regularFontInfo.atlas.shadowHeight
     }
 
     override fun getBelowLineHeight(): Float {
-        return regularFont.fontInfo.atlas.belowLineHeight
+        return regularFontInfo.atlas.belowLineHeight
     }
 
     private fun drawStringNow(
@@ -194,7 +195,7 @@ class BasicFontRenderer(
             }
 
 
-            val glyph = regularFont.fontInfo.glyphs[char.code]
+            val glyph = regularFontInfo.glyphs[char.code]
             if (glyph == null) {
                 i++
                 continue
@@ -203,34 +204,34 @@ class BasicFontRenderer(
             val planeBounds = glyph.planeBounds
 
             if (planeBounds != null) {
-                val width = (planeBounds.right - planeBounds.left) * originalPointSize
-                val height = (planeBounds.top - planeBounds.bottom) * originalPointSize
+                val width = (planeBounds.r - planeBounds.l) * originalPointSize
+                val height = (planeBounds.t - planeBounds.b) * originalPointSize
 
                 drawGlyph(
                     vertexConsumer,
                     matrixStack,
                     glyph,
                     color,
                     currentX,
-                    y + planeBounds.bottom * originalPointSize,
+                    y + regularFontInfo.atlas.baseCharHeight - planeBounds.t * originalPointSize,
                     width,
                     height
                 )
             }
 
-            //The texture atlas is used here because in the context of this implementation of the font renderer
-            //we do not need or want the full precision the msdf font renderer exports in. Instead, we care about
-            //calculating width based on the texture pixels
-            if (glyph.atlasBounds != null) {
-                currentX += (((glyph.atlasBounds.right - glyph.atlasBounds.left) / regularFont.fontInfo.atlas.size) * originalPointSize)
-            } else {
-                currentX += (glyph.advance) * originalPointSize
-            }
+            currentX += computeAdvance(regularFontInfo, glyph) * originalPointSize
             i++
         }
 
     }
 
+    // Letter spacing for many fonts is like 1.25px, so we ignore font-provided advance values, and instead derive
+    // ones directly based on the actual size of the glyph.
+    private fun computeAdvance(fontInfo: FontInfo, glyph: Glyph): Float =
+        if (glyph.atlasBounds != null) (glyph.atlasBounds.r - glyph.atlasBounds.l + 1) / fontInfo.atlas.size
+        // For empty glyphs (like ` `), we use the font-provided value but round it to pixels so we don't end up with
+        // sub-pixel positions. We don't use `roundToRealPixels`, so the value stays scale-independent.
+        else (glyph.advance * fontInfo.atlas.size).roundToInt() / fontInfo.atlas.size
 
     private fun drawGlyph(
         worldRenderer: UVertexConsumer,
@@ -243,11 +244,11 @@ class BasicFontRenderer(
         height: Float
     ) {
         val atlasBounds = glyph.atlasBounds ?: return
-        val atlas = regularFont.fontInfo.atlas
-        val textureTop = 1.0 - ((atlasBounds.top) / atlas.height)
-        val textureBottom = 1.0 - ((atlasBounds.bottom) / atlas.height)
-        val textureLeft = (atlasBounds.left / atlas.width).toDouble()
-        val textureRight = (atlasBounds.right / atlas.width).toDouble()
+        val atlas = regularFontInfo.atlas
+        val textureTop = 1.0 - ((atlasBounds.t) / atlas.height)
+        val textureBottom = 1.0 - ((atlasBounds.b) / atlas.height)
+        val textureLeft = (atlasBounds.l / atlas.width).toDouble()
+        val textureRight = (atlasBounds.r / atlas.width).toDouble()
 
         val doubleX = x.toDouble()
         val doubleY = y.toDouble()
@@ -290,4 +291,4 @@ class BasicFontRenderer(
             blendState = BlendState.ALPHA
         }.build()
     }
-}
+}

src/main/kotlin/gg/essential/elementa/font/data/FontInfo.kt

@@ -62,16 +62,21 @@ data class PlaneBounds(
     @SerializedName("top")
     private val _top: Float
 ) {
-    /**
-     * msdfgen exports the plane locations with .025 subtracted from the
-     * Y coordinate of each glyph, so we must correct for this
-     */
+    val l: Float get() = _left
+    val b: Float get() = _bottom
+    val r: Float get() = _right
+    val t: Float get() = _top
+
+    @Deprecated("Returns incorrect value") // technically this one's right, but `top` and `bottom` aren't
     val left: Float
         get() = _left
+    @Deprecated("Returns incorrect value")
     val bottom: Float
         get() = _bottom + 0.025f
+    @Deprecated("Returns incorrect value") // technically this one's right, but `top` and `bottom` aren't
     val right: Float
         get() = _right
+    @Deprecated("Returns incorrect value")
     val top: Float
         get() = _top + 0.025f
 }
@@ -87,17 +92,47 @@ data class AtlasBounds(
     @SerializedName("top")
     private val _top: Float
 ) {
-    /**
-     * msdfgen exports UV locations in the middle of pixels.
-     * This causes the rendering to occur slightly of from
-     * where you would expect it and incorrect texel mapping.
-     */
+    val l: Float get() = _left
+    val b: Float get() = _bottom
+    val r: Float get() = _right
+    val t: Float get() = _top
+
+    @Deprecated("Returns incorrect value")
     val left: Float
         get() = _left + .5f
+    @Deprecated("Returns incorrect value")
     val bottom: Float
         get() = _bottom + .5f
+    @Deprecated("Returns incorrect value")
     val right: Float
         get() = _right + .5f
+    @Deprecated("Returns incorrect value")
     val top: Float
         get() = _top + .5f
 }
+
+/**
+ * msdfgen inflates all glyphs by half a pixel so all the edges are drawn properly when using MSDF.
+ * This function un-does that, because we don't need it in our pixel-font renderer
+ * ([gg.essential.elementa.font.BasicFontRenderer]) and it makes any sizing math more difficult.
+ */
+internal fun FontInfo.shrinkGlyphsByHalfAPixel(): FontInfo {
+    val a = 0.5f // half a pixel in atlas coordinates
+    val p = a / atlas.size // half a pixel in plane coordinates
+    return FontInfo(
+        atlas,
+        metrics,
+        glyphs.mapValues { (_, glyph) ->
+            Glyph(
+                glyph.unicode,
+                glyph.advance,
+                glyph.planeBounds?.let { bounds ->
+                    PlaneBounds(bounds.l + p, bounds.b + p, bounds.r - p, bounds.t - p)
+                },
+                glyph.atlasBounds?.let { bounds ->
+                    AtlasBounds(bounds.l + a, bounds.b + a, bounds.r - a, bounds.t - a)
+                },
+            )
+        },
+    )
+}

src/main/resources/fonts/Minecraft-Five.json

@@ -5,7 +5,7 @@
     "width": 64,
     "height": 64,
     "yOrigin": "bottom",
-    "baseCharHeight": 5.0,
+    "baseCharHeight": 6.0,
     "belowLineHeight": 1.0,
     "shadowHeight": 1.0
   },
@@ -942,9 +942,9 @@
       "advance": 0.80000000000000004,
       "planeBounds": {
         "left": 0.025000000000000029,
-        "bottom": 0.475,
+        "bottom": -0.19500000000000001,
         "right": 0.77500000000000002,
-        "top": 0.72499999999999998
+        "top": 0.055
       },
       "atlasBounds": {
         "left": 40.5,