add axis labels and minor grid; change grid colour to grey

plots/plots.py

@@ -193,9 +193,22 @@ def major_grid(pixel_extent):
         mantissa = min_extent/10**exponent
         major = 1.0
         for m in (2.0, 5.0, 10.0):
-            if mantissa < m:
+            if m > mantissa:
                 major = m * 10**exponent
-                return major
+                minor = major / (4 if m == 2 else 5)
+                return major, minor
+
+    def graph_to_device(self, graph_pos):
+        normalised = (graph_pos + self.translation)/self.scale
+        gl_pos = normalised / self.viewport * self.viewport[0]
+        gl_pos[1] *= -1
+        return (gl_pos/2 + 0.5) * self.viewport
+
+    def device_to_graph(self, pixel):
+        gl_pos = 2*(pixel/self.viewport - 0.5)
+        gl_pos[1] *= -1
+        normalised = gl_pos * self.viewport / self.viewport[0]
+        return normalised*self.scale - self.translation
 
     def gl_render(self, area, context):
         area.make_current()
@@ -213,18 +226,41 @@ def gl_render(self, area, context):
         glEnable(GL_DEPTH_TEST)
         glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
 
+        major_grid, minor_grid = self.major_grid(pixel_extent[0])
         shaders.glUseProgram(self.shader)
         glUniform2f(self.uniform("viewport"), *self.viewport)
         glUniform2f(self.uniform("translation"), *self.translation)
         glUniform2f(self.uniform("pixel_extent"), *pixel_extent)
         glUniform1f(self.uniform("scale"), self.scale)
-        glUniform1f(self.uniform("major_grid"), self.major_grid(pixel_extent[0]))
+        glUniform1f(self.uniform("major_grid"), major_grid)
+        glUniform1f(self.uniform("minor_grid"), minor_grid)
         for slider in self.slider_rows:
             glUniform1f(self.uniform(slider.name), slider.value)
         glBindVertexArray(self.vao)
         glDrawArrays(GL_TRIANGLES, 0, 18)
         glBindVertexArray(0)
-        self.text_renderer.render(w, h)
+        with self.text_renderer.render(w, h) as r:
+            low = major_grid * np.floor(
+                self.device_to_graph(np.array([0, h]))/major_grid)
+            high = major_grid * np.ceil(
+                self.device_to_graph(np.array([w, 0]))/major_grid)
+            n = (high - low)/major_grid
+            pad = 4
+            for i in range(round(n[0])+1):
+                x = low[0] + i*major_grid
+                pos = self.graph_to_device(np.array([x, 0]))
+                pos[1] = np.clip(pos[1] + pad, pad, self.viewport[1] - r.top_bearing - pad)
+                if x:
+                    r.render_text("%g" % x, pos, valign='top', halign='center')
+            for j in range(round(n[1])+1):
+                y = low[1] + j*major_grid
+                label = "%g" % y
+                pos = self.graph_to_device(np.array([0, y]))
+                pos[0] = np.clip(pos[0] - pad, r.width_of(label) + pad, self.viewport[0] - pad)
+                if y:
+                    r.render_text(label, pos, valign='center', halign='right')
+            r.render_text("0", self.graph_to_device(np.zeros(2)) + np.array([-pad, pad]),
+                          valign='top', halign='right')
         return True
 
     def uniform(self, name):

plots/shaders/fragment.glsl

@@ -24,6 +24,7 @@ out vec4 rgba;
 uniform vec2 pixel_extent;
 uniform float scale;
 uniform float major_grid;
+uniform float minor_grid;
 
 #define pi 3.141592653589793
 #define e 2.718281828459045
@@ -142,9 +143,11 @@ void main() {
     {% endfor %}
 
     float axis_width = pixel_extent.x;
-    color -= (1.0-vec3(0.2,0.2,1.0))*(1.0-smoothstep(axis_width, axis_width*1.05, abs(graph_pos.x)));
-    color -= (1.0-vec3(0.2,0.2,1.0))*(1.0-smoothstep(axis_width, axis_width*1.05, abs(graph_pos.y)));
-    color -= (1.0-vec3(0.8,0.8,1.0))*(1.0-smoothstep(axis_width, axis_width*1.05, abs(mod(graph_pos.x, major_grid))));
-    color -= (1.0-vec3(0.8,0.8,1.0))*(1.0-smoothstep(axis_width, axis_width*1.05, abs(mod(graph_pos.y, major_grid))));
+    color -= (1.0-vec3(0.2,0.2,0.2))*(1.0-smoothstep(axis_width*.6, axis_width*.65, abs(graph_pos.x)));
+    color -= (1.0-vec3(0.2,0.2,0.2))*(1.0-smoothstep(axis_width*.6, axis_width*.65, abs(graph_pos.y)));
+    color -= (1.0-vec3(0.7,0.7,0.7))*(1.0-smoothstep(axis_width, axis_width*1.05, abs(mod(graph_pos.x, major_grid))));
+    color -= (1.0-vec3(0.7,0.7,0.7))*(1.0-smoothstep(axis_width, axis_width*1.05, abs(mod(graph_pos.y, major_grid))));
+    color -= (1.0-vec3(0.9,0.9,0.9))*(1.0-smoothstep(axis_width, axis_width*1.05, abs(mod(graph_pos.x, minor_grid))));
+    color -= (1.0-vec3(0.9,0.9,0.9))*(1.0-smoothstep(axis_width, axis_width*1.05, abs(mod(graph_pos.y, minor_grid))));
     rgba = vec4(color, 1);
 }

plots/shaders/text_frag.glsl

@@ -30,5 +30,5 @@ void main()
 {
     vec2 uv = vUV.xy;
     float text = texture(u_texture, uv).r;
-    fragColor = vec4(textColor.rgb*text, text);
+    fragColor = vec4(vec3(1-text), clamp(text, 0.8, 1));
 }

plots/text.py

@@ -27,6 +27,7 @@
     import importlib.resources as resources
 except ModuleNotFoundError:
     import importlib_resources as resources
+from contextlib import contextmanager
 
 
 # Code based on:
@@ -40,7 +41,7 @@ def __init__(self):
         self.width, self.height = 0, 0
         self.characters = []
         self.initgl()
-        self.fontsize = 12
+        self.fontsize = 14
         self.makefont(resources.open_binary('plots.res', 'DejaVuSans.ttf'),
                       self.fontsize)
 
@@ -76,22 +77,23 @@ def makefont(self, filename, fontsize):
         glPixelStorei(GL_UNPACK_ALIGNMENT, 1)
         glActiveTexture(GL_TEXTURE0)
 
+        self.top_bearing = 0
         for c in range(128):
             face.load_char(chr(c), freetype.FT_LOAD_RENDER)
             glyph = face.glyph
             bitmap = glyph.bitmap
             size = bitmap.width, bitmap.rows
             bearing = glyph.bitmap_left, glyph.bitmap_top
+            self.top_bearing = max(self.top_bearing, bearing[1])
             advance = glyph.advance.x
 
             # create glyph texture
             texObj = glGenTextures(1)
             glBindTexture(GL_TEXTURE_2D, texObj)
-            glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
-            glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
             glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE)
             glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE)
-            #databuffer = np.zeros((cx, width*16), dtype=np.ubyte)
             glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, *size, 0, GL_RED, GL_UNSIGNED_BYTE, bitmap.buffer)
 
             self.characters.append((texObj, size, bearing, advance))
@@ -102,23 +104,35 @@ def makefont(self, filename, fontsize):
     def uniform(self, name):
         return glGetUniformLocation(self.shaderProgram, name)
 
+    @contextmanager
     def render(self, width, height):
         self.width, self.height = width, height
         glUseProgram(self.shaderProgram)
         proj = glm.ortho(0, self.width, self.height, 0, -1, 1)
         glUniformMatrix4fv(self.uniform("projection"),
                            1, GL_FALSE, glm.value_ptr(proj))
-
-        glUniform3f(self.uniform("textColor"), 0.2, .2, .2)
-        self.render_text("This is sample text", (0, 12), 1, (1, 0))
-
-    def render_text(self, text, pos, scale, dir):
+        yield self
+
+    def width_of(self, text, scale=1):
+        return sum((self.characters[ord(c)][3] >> 6)*scale for c in text)
+
+    def render_text(self, text, pos, scale=1, dir=(1,0), halign='left', valign='bottom'):
+        offset = glm.vec3()
+        if halign in ('center', 'right'):
+            width = self.width_of(text, scale)
+            offset.x -= width
+            if halign == 'center':
+                offset.x /= 2
+        if valign in ('center', 'top'):
+            offset.y += self.top_bearing
+            if valign == 'center':
+                offset.y /= 2
         glActiveTexture(GL_TEXTURE0)
         glBindVertexArray(self.vao)
         angle_rad = math.atan2(dir[1], dir[0])
         rotateM = glm.rotate(glm.mat4(1), angle_rad, glm.vec3(0, 0, 1))
-        transOriginM = glm.translate(glm.mat4(1), glm.vec3(*pos, 0))
-
+        transOriginM = glm.translate(glm.mat4(1), glm.vec3(*pos, 0) + offset)
+        glUniform3f(self.uniform("textColor"), .0, .0, .0)
         char_x = 0
         for c in text:
             c = ord(c)