Allow specifying a texture font's char size in the text file defining the characters in the texture. Also loading said text file via MC's resource system which should make it replaceable using resource packs. Probably.

src/main/resources/assets/opencomputers/textures/font/chars.txt

@@ -1 +1,2 @@
 ☺☻♥♦♣♠•◘○◙♂♀♪♫☼►◄↕‼¶§▬↨↑↓→←∟↔▲▼ !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~⌂ÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜ¢£¥₧ƒáíóúñѪº¿⌐¬½¼¡«»░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■
+5 9

src/main/scala/li/cil/oc/client/renderer/MonospaceFontRenderer.scala

@@ -3,22 +3,34 @@ package li.cil.oc.client.renderer
 import li.cil.oc.client.Textures
 import li.cil.oc.util.{RenderState, PackedColor}
 import li.cil.oc.{OpenComputers, Settings}
+import net.minecraft.client.Minecraft
 import net.minecraft.client.renderer.GLAllocation
 import net.minecraft.client.renderer.texture.TextureManager
+import net.minecraft.util.ResourceLocation
 import org.lwjgl.opengl.GL11
 import scala.io.Source
 
 object MonospaceFontRenderer {
-  private val chars = Source.fromInputStream(MonospaceFontRenderer.getClass.getResourceAsStream("/assets/" + Settings.resourceDomain + "/textures/font/chars.txt"))("UTF-8").mkString
+  val (chars, fontWidth, fontHeight) = try {
+    val lines = Source.fromInputStream(Minecraft.getMinecraft.getResourceManager.getResource(new ResourceLocation(Settings.resourceDomain, "/textures/font/chars.txt")).getInputStream)("UTF-8").getLines
+    val chars = lines.next()
+    val (w, h) = if (lines.hasNext) {
+      val size = lines.next().split(" ", 2)
+      (size(0).toInt, size(1).toInt)
+    } else (5, 9)
+    (chars, w, h)
+  }
+  catch {
+    case t: Throwable =>
+      OpenComputers.log.warning("Failed reading font metdata, using defaults.")
+      ("""☺☻♥♦♣♠•◘○◙♂♀♪♫☼►◄↕‼¶§▬↨↑↓→←∟↔▲▼ !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~⌂ÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜ¢£¥₧ƒáíóúñѪº¿⌐¬½¼¡«»░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■""", 5, 9)
+  }
 
   private var instance: Option[Renderer] = None
 
   def init(textureManager: TextureManager) = this.synchronized(
     instance = instance.orElse(Some(new Renderer(textureManager))))
 
-  val fontWidth = 5
-  val fontHeight = 9
-
   def drawString(x: Int, y: Int, value: Array[Char], color: Array[Short], format: PackedColor.ColorFormat) = this.synchronized(instance match {
     case None => OpenComputers.log.warning("Trying to render string with uninitialized MonospaceFontRenderer.")
     case Some(renderer) => renderer.drawString(x, y, value, color, format)