Optimize output with mixed pow/subscript.

This fixes:
https://github.com/ArthurSonzogni/Diagon/issues/1

src/translator/math/Math.cpp

@@ -150,6 +150,19 @@ Draw ComposeDiagonalDown(const Draw& A, const Draw& B) {
   return composition;
 }
 
+// Useful for x_a^b
+Draw ComposeDiagonalUpAndDown(const Draw& A, const Draw& B, const Draw& C) {
+  Draw composition;
+  composition.Append(B, A.dim_x, 0);
+  composition.Append(A, 0, B.dim_y);
+  composition.Append(C, A.dim_x, B.dim_y + A.dim_y);
+
+  composition.center_x = composition.dim_x / 2;
+  composition.center_y = A.center_y + B.dim_y;
+
+  return composition;
+}
+
 Draw WrapWithParenthesis(const Draw& element, Style* style) {
   Draw draw;
   draw.Resize(element.dim_x + 2, element.dim_y);
@@ -340,6 +353,21 @@ Draw Parse(MathParser::FactorContext* context,
            bool suppress_parenthesis) {
   suppress_parenthesis &= (context->valueBang().size() == 1);
   Draw draw = Parse(context->valueBang(0), style, suppress_parenthesis);
+
+  // Optimization for a_b^c and a^c:
+  if (context->valueBang().size() == 3) {
+    if (context->powop(0)->POW() && context->powop(1)->SUBSCRIPT()) {
+      return ComposeDiagonalUpAndDown(
+          draw, Parse(context->valueBang(1), style, false),
+          Parse(context->valueBang(2), style, false));
+    }
+    if (context->powop(1)->POW() && context->powop(0)->SUBSCRIPT()) {
+      return ComposeDiagonalUpAndDown(
+          draw, Parse(context->valueBang(2), style, false),
+          Parse(context->valueBang(1), style, false));
+    }
+  }
+
   for (int i = 1; i < context->valueBang().size(); ++i) {
     auto* compose =
         context->powop(i - 1)->POW() ? ComposeDiagonalUp : ComposeDiagonalDown;

test/Math/mixed_pow_subscript/output

@@ -1,7 +1,7 @@
-  3
-A  
- 2 
-   
- 2 
-A  
-  3
+ 3
+A 
+ 2
+  
+ 2
+A 
+ 3

test/Math_style=ASCII/mixed_pow_subscript/output

@@ -1,7 +1,7 @@
-  3
-A  
- 2 
-   
- 2 
-A  
-  3
+ 3
+A 
+ 2
+  
+ 2
+A 
+ 3

test/Math_style=Latex/braces/output

@@ -1,7 +1,7 @@
-A_\left(1 + 2\right) \\
+A_{\left(1 + 2\right)} \\
 \\
-A_1 + 2 \\
+A_{1 + 2} \\
 \\
-A^\left(1 + 2\right) \\
+A^{\left(1 + 2\right)} \\
 \\
-A^1 + 2
+A^{1 + 2}

test/Math_style=Latex/integral/output

@@ -1,10 +1,10 @@
 \int_{b}^{c} a \\
 \\
-\int_{x = 1}^{100} x^2 \\
+\int_{x = 1}^{100} x^{2} \\
 \\
 \int_{x = 1}^{100} \frac{1}{2} \\
 \\
-\int_{x = 1}^{100} \frac{x^2}{2} \\
+\int_{x = 1}^{100} \frac{x^{2}}{2} \\
 \\
 \int_{bbbbbbbbbbbb}^{c} a \\
 \\

test/Math_style=Latex/mixed_pow_subscript/output

@@ -1,3 +1,3 @@
-A_2^3 \\
+A_{2}^{3} \\
 \\
-A^2_3
+A^{2}_{3}

test/Math_style=Latex/pow/output

@@ -1,11 +1,11 @@
-A^2 \\
+A^{2} \\
 \\
-A^\left(\frac{1}{2}\right)^\sqrt{2} \\
+A^{\left(\frac{1}{2}\right)}^{\sqrt{2}} \\
 \\
-\left(A^\left(\frac{1}{2}\right)\right)^\sqrt{2} \\
+\left(A^{\left(\frac{1}{2}\right)}\right)^{\sqrt{2}} \\
 \\
-A^\left(\left(\frac{1}{2}\right)^\sqrt{2}\right) \\
+A^{\left(\left(\frac{1}{2}\right)^{\sqrt{2}}\right)} \\
 \\
-A^421 + \frac{1}{2} \\
+A^{421} + \frac{1}{2} \\
 \\
-\frac{A^421}{2}
+\frac{A^{421}}{2}

test/Math_style=Latex/speed/output

@@ -1 +1 @@
-speed = \sqrt{\left(\frac{df}{dx}\right)^2 + \left(\frac{df}{dy}\right)^2}
+speed = \sqrt{\left(\frac{df}{dx}\right)^{2} + \left(\frac{df}{dy}\right)^{2}}

test/Math_style=Latex/string/output

@@ -1,7 +1,7 @@
 "hello world" \\
 \\
-"A_B"_"C_D" \\
+"A_B"_{"C_D"} \\
 \\
 "" \\
 \\
-1^"2^3"^4
+1^{"2^3"}^{4}

test/Math_style=Latex/subscript/output

@@ -1,11 +1,11 @@
-A_2 \\
+A_{2} \\
 \\
-A_\left(\frac{1}{2}\right)_\sqrt{2} \\
+A_{\left(\frac{1}{2}\right)}_{\sqrt{2}} \\
 \\
-\left(A_\left(\frac{1}{2}\right)\right)_\sqrt{2} \\
+\left(A_{\left(\frac{1}{2}\right)}\right)_{\sqrt{2}} \\
 \\
-A_\left(\left(\frac{1}{2}\right)_\sqrt{2}\right) \\
+A_{\left(\left(\frac{1}{2}\right)_{\sqrt{2}}\right)} \\
 \\
-A_421 + \frac{1}{2} \\
+A_{421} + \frac{1}{2} \\
 \\
-\frac{A_421}{2}
+\frac{A_{421}}{2}

test/Math_style=Latex/sum/output

@@ -1,10 +1,10 @@
 \sum_{b}^{c} a \\
 \\
-\sum_{x = 1}^{100} x^2 \\
+\sum_{x = 1}^{100} x^{2} \\
 \\
 \sum_{x = 1}^{100} \frac{1}{2} \\
 \\
-\sum_{x = 1}^{100} \frac{x^2}{2} \\
+\sum_{x = 1}^{100} \frac{x^{2}}{2} \\
 \\
 \sum_{bbbbbbbbbbbb}^{c} a \\
 \\

test/Math_style=Latex/variable/output

@@ -4,7 +4,7 @@ f'\left(x\right) \\
 \\
 a123456789°à@çè|#~#& \\
 \\
-2_2m \\
+2_{2m} \\
 \\
 2é8fsdmoiuuç \\
 \\